扒哥吃瓜

This background quality report relates to the publication of听sea passenger statistics.听

The purpose of this document is to provide users of the statistics with information about the quality of the outputs, measured against different dimensions of statistical quality.听

As a result, this document helps to听demonstrate听how the Department听for Transport (DfT)听complies with听the Code of Practice for Official Statistics principle on quality.听

These听statistics were independently reviewed by the Office for Statistics Regulation in鈥疐ebruary 2013鈥痑nd are therefore labelled鈥� .听Accredited official statistics听are produced to high professional standards as set out in the . They undergo regular quality assurance to ensure they meet customer needs.听

Section 1: Background to the statistics听

These statistics cover international and domestic听sea听passengers, with data collected and published differently for听different types听of听route. They are collected for a range of听uses.听

International short sea ferry passenger statistics are collected monthly from ferry operators. They include drivers of lorries,听coaches听and other vehicles. Passenger figures for domestic ferry routes from Great Britain to Northern Ireland, the Channel Islands and the Isle of Man are also collected but not published monthly.听

Cruise passenger figures include all passengers on听cruise journeys who听embark听and听disembark听their cruise journey at a UK port.听Cruise passenger numbers are included in our statistics only for passengers at UK ports, whether they are听departing, arriving or both.听Passengers passing through on transit calls are not included in these figures.听Cruise figures are compiled on an annual basis. Long sea voyage passengers are those travelling on one-way scheduled voyages to and from ports outside Europe听or the听Mediterranean. Passengers travelling on cargo vessels (one way) are not collected.听听

In 2021, passenger numbers on UK domestic cruises were collected for the first time. Large domestic cruises did not previously occur but were a feature in 2021 due to the start of domestic cruising which was carried out as part of the gradual lifting of coronavirus restrictions when the听Foreign听office听advised听against international sea-going cruise travel due to public health medical advice. Domestic cruise passenger figures include all passengers on domestic cruises in the UK (no cruise stops at foreign ports).听

Domestic ferry passenger figures on sea crossings to Orkney and Shetland are provided on an annual basis by the Scottish Government. Figures for some other sea crossings and river ferries are also provided annually by the operators.听

Sea passenger statistical publications are published in two parts. Total international short sea passenger numbers are published monthly. The annual publication is published in听July听each year and includes all international and domestic passengers for which data are collected.听

For further information, including a breakdown of the routes covered, see the听.听

Map 1: Map of UK听major ports covered in sea passenger statistics听

Methodology and Production听

Sea passenger data is collected using surveys, which are sent to operators as email attachments. The process is听outlined below.听

听The monthly collection covers passengers on short sea routes with UK ports on vessels over 100 gross tonnes. A form with cover letter and instructions are sent to operators.听听

The annual domestic passenger collection data听(as with the monthly collection) is restricted to vessels over 100 gross tonnes.听The collection includes river ferries in the UK that have a distance greater than 500 metres and passenger kilometres greater than 500.听听

The annual cruise collection includes cruise ships which return to the port of departure as well as those which let passengers off at a destination port. The operators label the type of cruise as听鈥淓urope鈥�,听鈥渨orld鈥� or 鈥渓iner鈥�.听Europe and world cruises are classed as 鈥渃ruise鈥� in the data. Liner cruises are classed as 鈥渓ong sea鈥� in the data. The definitions of each cruise are:听

• Europe (E) - cruise in Europe听or the听Mediterranean (including one way trip)听

• World (W) - cruise outside Europe听or the听Mediterranean (excluding听one way听trips)听

• Liner (L) - voyage (one way voyage to or from a port outside Europe听and the听Mediterranean)听

Future development work will review the area of cruise classification to better align with industry terminology. We welcome user feedback on whether alternative classifications would better meet their needs.

In 2025, we began collecting data on cruise transit passengers as part of our ongoing work to improve coverage of passenger movements. Work is underway with industry partners to develop a reliable time series for transit passengers and assess the quality and completeness of the data, and we are grateful to those operators who have provided data to support this work so far. We welcome feedback from stakeholders on the collection and potential future uses of these statistics as the data matures.

For each monthly and annual collection process, data returns are collated together using R (a statistical programming software).听

The Department for Transport (DfT)听validates听the data to verify that the data items are听accurate听and consistent. This includes checking for duplicates, missing data and any anomalies, particularly flagging figures that are either considerably high or low compared to the听previous month or听year. These checks are done using R.听

Any anomalies are investigated and where we believe they may be听inaccurate,听queries are sent back to the operator for confirmation of the data. DfT then signs off the data for use in production of the statistics.听听

Once the data is finalised, it is entered into a SQL/GCP听database, where data tables are exported to Excel and the tables and statistical release are produced for publication. Further checks are then carried out, for example looking at trends over time.听

Each statistical release produced is independently checked by a statistician where any discrepancies are resolved before being approved by the senior statistician.听

Section 2: Quality assessment听

In this section, the quality of the statistics is considered in relation to the different dimensions of quality as听stated听in the .听

听1. Relevance听

The statistical outputs presented within sea passenger statistics include:听

• A听statistical release听containing key findings, trends over time and signposts to further information.听听

• Open Document Spreadsheet (ODS)听data tables听containing听information on the number passengers by port and ferry route听

• A听听that displays interactive visualisation of international听sea passenger volumes by journey type, UK听port听and destinations听

• A听notes and definitions document听outlining route level breakdown and strengths and weaknesses听

Known users and uses of the statistics

Within the DfT the statistics are used:听

• For ministerial briefing and to answer public enquiries听

• As background to policy development, for example as an evidence base for cyber security policy decisions听

• For monitoring trends in sea passenger activity听

• By analysts in modelling overall passenger trends, or for ad-hoc work for example related to assessing the scale and impact of disruption to key routes听

Outside of DfT, known users include:听

• Operators of sea passenger services, port authorities and any other maritime organisations听monitoring听sea passenger activity听

• The Office for National Statistics use monthly data for grossing the international passenger survey and in their statistical releases听听

• MET police, who occasionally use the data to help inform policing of ports operation听

• Home Office, who use data in preparing their听accredited official statistics听release (immigration statistics)听

• Other more general users who want to gain an overview of the sea passenger business, and for benchmarking听

How well the statistics meet user needs听

DfT carried out an internal review of the sea passenger statistics in 2017 to assess if the statistics are compliant with the听. The review covered things like, timeliness of the publication, explored the need for other potential data sources and checked to see if the statistical series is meeting user needs.听听

While the conclusion was that the statistics are听generally fit听for the purposes for which they are used,听a number of听requests were noted. These are summarised below, along with the department鈥檚 response.听

User requests	Outcome
A breakdown of the figures for domestic passengers by individual route.	The department has checked with operators whether they would be content for a more detailed breakdown by route to be published. However, the data at this level are considered commercially sensitive, and data suppliers did not want DfT to publish further data on individual routes.	听
The number of cars, coaches and lorries carried, as well as passengers.	Data on vehicles can be found in tables PORT0301 and PORT0205 of the Port Freight statistics published by听DfT.	听
A distinction between foot passengers and passengers travelling by vehicle.	Whilst this data has been collected on an ad-hoc basis from some operators, we do not feel there is currently sufficient demand to increase the burden on operators.	听
Operators鈥� forecast of passengers and vehicles carried.	These forecasts are commercially听sensitive,听therefore we are unable to include them in the publication.	听
Monthly data for domestic short sea passengers.	Due to the way domestic data are collected (monthly and annual), we will听maintain听the current approach to aggregate it annually unless there are further user requests for monthly data.	听
Increase coverage of the statistics to include other services (e.g. those using vessels under 100 gross tonnes)	DfT considers that the added value of seeking to collect data for these services would not justify the increased burden of data collection, which would fall on smaller operators. The consistency of the published time series would also be affected.	听

听2. Accuracy and reliability听

These statistics aim to measure the true number of sea passengers travelling to and from UK ports. Overall, high level comparisons with industry sources (where available) and trends over time suggest that the statistics are likely to provide a consistent approximation overall, though it is possible that in some areas (e.g. cruise passengers and domestic services) figures are slightly under-estimated.听听

The听following summarises potential sources of risks or errors which may arise throughout the process of compiling the sea passenger statistics.听

Potential source of error	Risk of error mitigation
International Maritime Organisation identification number听(IMO) errors - invalid vessels	听IMO听is a unique vessel identifier. The most common error with听IMO听is that the contributor will have made a typo. There are validation checks in place which flags when the听IMO听number is greater than or less than 7 numbers. The validation also flags if it does not recognise the听IMO. DfT then will rectify all the flagged听IMO鈥檚.	听
Number of sailing errors	If there are big discrepancies between the number of sailings arriving and听departing, DfT will query with the operators to confirm the data.	听
Duplicate entries	Duplicate entries are听identified, confirmed with听operators听and deleted.	听
Unexpected routes	Unexpected routes are flagged and queried with an operator to check if the new route is accurate.	听
Passenger numbers	Passenger figures by routes are compared to the same month previous year. Figures are investigated if they exceed or are below the 20% benchmark.	听
Missing data	On rare occasions, when the DfT get no response from operators, we estimate the data. The estimation is based on an average of听previous听records.	听
Port听locode听errors	听Locodes听are port identifiers. Typos and incorrect听locodes听are picked up by validation routines run before the data is processed into the database.	听
New operator or route	We are continuously on the lookout for new operators or routes (for example monitoring trade press), to avoid underestimating passenger numbers wherever possible.	听

听3. Timeliness and Punctuality听

Sea passenger statistics are currently published monthly SPAS0107听and听annually听(all other听tables听for international, cruise and domestic passengers are published in听August). The production of the monthly table听commences听in the middle of the month once the data has been collected. The table is finalised and published 6 weeks after the reference month.听Cruise and domestic data听is听collected from January to April, with the data cleaned and听validated听in May and June. The annual release is started at the end of June and published in听August.听听

To date, all sea passenger statistical releases have been published to the scheduled pre-announced date.听

听4. Accessibility and Clarity听

Accessibility:听

The outputs are published on the 扒哥吃瓜 DfT statistics page in accessible formats.听

Statistical releases are available as html files, which are accessible for those who use assistive technologies.听

Data tables are available in ODS file format which can be accessed by using freely available software. The spreadsheets have been designed to be used easily by assistive technologies.听The published tables include information on the passenger numbers by port, ferry听route听and country of destination.听

Clarity:听

The statistical releases use plain language, in which technical terms, acronyms and definitions are defined where听appropriate. The main findings are presented using a series of text,听charts听and maps,听with maps used to show the location of the major ports. Full details of the strengths and weaknesses of the data are provided at the end of each statistical report for users who are interested in this. In addition to the statistical releases, a听notes and definitions document听has been published which lists the routes the sea passenger series covers as well as the key definitions.听

5. Coherence and Comparability听

Comparability:听

The statistical series for international sea passengers covers trends since 1950 for all short sea routes. The data听are considered to be听comparable over time, showing an increase in sea passenger journeys up to 1994 (when the Channel Tunnel opened). Since听then,听there has been a slow decline in sea passenger numbers.听

Long sea journeys are also considered broadly comparable over time. The trends for long sea journeys during the 1950s to the 1970s show liner journeys were popular for inter-continental travel. Since听then,听there has been a decrease, likely to be due to the increase in demand for air travel. Numbers can fluctuate due to the use of journeys to reposition vessels by some operators.听

Comparison with figures produced by industry bodies suggests that the trend shown for cruise journeys are reliable; however, a port survey carried out in early 2013 resulted in more cruise data becoming available for Harwich, Newcastle and Portsmouth, which may impact on the trends shown for these ports (at the overall level the impact is likely to be minor, compared to the real increase in demand for cruises).听

A larger operator returned figures in 2019 that听hadn鈥檛听been provided previously, with vessels听operating听at the port of Dover. This contributed to an increase in cruise passengers at this port.听

Furlough of port employees for Aberdeen and Inverness due to the coronavirus (COVID-19) pandemic meant that figures for these ports could not be included in 2019. Both reporting issues mentioned were assessed to be听small compared听to the total and did not听impact听the overall trends for cruises and long sea passengers.听

The domestic sea passenger movements are听on the whole听considered to reflect trends over听time,听however figures can be affected by changes in operator recording practices (for example part of the increase in river ferry passengers in the 2017 statistics is attributed to a change in recording by a large operator).听

Coherence:听

For cruises, an industry body 鈥� Cruise Lines International Association (CLIA) 鈥� also publish statistics on UK resident passengers.听CLIA figures do not count the same thing as they are counting UK residents on cruises ships across the world, and therefore the numbers do not match the DfT source. However, trends across the two data sources听generally align听when there are any increases or decreases in passenger numbers.听听

For other types of sea passengers, fewer sources are available to make comparisons.听

6. Trade-offs between Output Quality Components听

Previously, there were two annual statistical publications due to cruise and domestic data taking longer to collect. DfT have engaged with operators and have been able to bring the collection timescales forward. This means the data is ready to be published in听August听each year. As the data is ready earlier, the two publications have been combined into one release to improve the overall timeliness of our statistics for users.听

听7. Assessment of User Needs and Perceptions听

DfT regularly engages with users by social media,听email听and face to face methods when possible. This includes requesting feedback on the monthly and annual statistics series, with contact details provided in every statistical release. Each publication is promoted via Twitter.听

DfT also regularly analyses web page usage, ad-hoc requests and social media analytics to听monitor听activity over time. In line with the听, users will be informed about any changes or revisions to the data series. Less听frequently, the department reviews the statistics (last done in 2017) and presents key results at seminars, for example those arranged by the Transport Statistics User Group (last presentation on sea passenger statistics in March 2017). As part of the annual publication issued in November 2018, the department published a note to users listing changes made and proposals to the data tables that听accompany听the publication. This included informing known users about the planned changes and requesting feedback.听

In December 2018, the department conducted a user feedback survey to understand if the statistics continue to be fit for purpose and meet user needs. The survey also asked for views on the actions detailed in the note to users the department published (see above). A听summary of the听feedback听has been published detailing user responses to the survey and the department鈥檚 course of action as a result. One of these actions was to cease updating quarterly tables as, after assessment, the monthly table is sufficient to meet user needs.听

8. Performance, Cost and Respondent Burden听

The overall respondent burden related to these statistics听is considered to be听relatively small. There are around 20 operators that supply data monthly, typically larger ferry operators, and it is considered that in most cases the figures can be easily extracted from their administrative or management information systems (with the data being recorded by the company for other purposes), so that the only additional burden relates to the compilation of the monthly return.听

Cruise and long sea returns are provided monthly by some operators, and annually by others. Data returned consists of a list of passenger numbers by voyage which it is assumed are already captured in management information systems.听

The domestic sea passenger returns听are considered to be听generally straightforward, with operators permitted to provide best estimates where data are not held.听听

In DfT, the estimated resource involved in the sea passenger statistics is assumed to be under 0.5 FTE, which听is considered to be听proportionate.听

9. Confidentiality, Transparency and Security听

All data is stored,听accessed听and analysed using DfT secure IT systems. Data protection regulations are adhered to throughout the sea passenger statistics production process, and any information provided to DfT by operators are kept securely where access to data is controlled听in accordance with听departmental policy.听

The information used to compile these statistics provides details on company name, company code, port names, vessel听details听and figures for number of passengers and sailings arriving and听departing. Sensitive or personal passenger details are not collected. Passenger numbers by company are collected. However,听the published statistics do not include passenger figures by individual company,听as data is presented in an aggregated format. No statistical disclosure control methods are applied to the outputs, as the variables included in the statistics are not considered to be sensitive.听

DfT aims to publish as much data as is possible whilst ensuring that confidentiality is听maintained.听听

DfT adheres to the principles and protocols laid out in the听听and听comply with听pre-release access arrangements. The pre-release access lists are available on the DfT website.听

Section 3: Work done to develop these statistics in the last year听

Continued to develop and modernise the collection and streamline data validation, which includes (but not limited to):听

• aligning the submission of dates of arrival and departure in the Annual Cruise Survey so that further validation with automated identification system (AIS) ship tracking data can be done听

• updated a听听with inclusion of sea passenger statistics to allow users to explore maritime statistics in more depth听

• designed a data submission website for sea听passengers听suppliers with听additional听automated validation checks听

• supported the transfer of databases to cloud servers for more efficient querying and validating听

Section听4: Summary and conclusions听

This Background Quality Report presents information for users of the sea passengers statistics听covering听different aspects听of their quality. The听department concludes,听on the basis of听the assessment outline above, that the statistics are of a quality which is considered fit for the purposes for which the statistics are being used.听

Comments and feedback on this report, or any other aspect of these statistics are welcome, and can be provided by email to sea-passengers.stats@dft.gov.uk.

Further information about these statistics is available, including:听

• Sea passenger听statistics:听data tables听

• Sea passenger听statistics:听notes and definitions听