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This page describes the URI scheme that is used on the Legislation API.

The best way of finding out the URI for a particular piece of legislation is to search for it. A search on the title of a piece of legislation will redirect you to the proper URI for that item of legislation without you having to construct the URI yourself.

The Legislation API attempts to follow the guidance given in How to Publish Linked Data on the Web. We define three levels of URIs:

When you request an identifier URI, the response will usually be a 303 See Other redirection to a document URI. When you request a document URI, you will usually get a 200 OK response and a Content-Location header that will point to an appropriate representation URI based on the Accept headers that you use in the request.

Identifier URIs

We recommend that you link to identifier URIs.

Identifier URIs generally follow the template:{type}/{year}/{number}[/{section}]

However, legislation is often quoted without a chapter number, which can make it hard to automatically construct these URIs. If you don't know the chapter number for a piece of legislation, you can use a search URI of the form:{title}

If the title is recognised, this will result in a 301 Moved Permanently redirection to the canonical URI for the legislation. For example, requesting:

will result in a 301 Moved Permanently redirection to

On occasion, items of legislation have very similar titles, and the title search will result in multiple possibilities. In this case, the response will be a 303 Multiple Choices containing a simple XHTML document. For example, requesting

will result in a document such as

<html xmlns="">
    <title>300 Multiple Choices</title>
    <h2>300 Multiple Choices</h2>
      <li><a href="/id/uksi/2006/3189">The Disability Rights Commission Act 1999 (Commencement No.3) Order 2006</a></li>
      <li><a href="/id/uksi/2000/880">The Disability Rights Commission Act 1999 (Commencement No. 2 and Transitional Provision) Order 2000</a></li>
      <li><a href="/id/uksi/1999/2210">The Disability Rights Commission Act 1999 (Commencement No. 1 and Transitional Provision) Order 1999</a></li>
      <li><a href="/id/uksi/1999/17">Disability Rights Commission Act 1999</a></li>

Legislation Types

The legislation type codes are the same as those used on the Statute Law Database, and within the OPSI site. The list is:

Description Document Main Type URI abbreviation
Primary Legislation
UK Public General Acts UnitedKingdomPublicGeneralAct ukpga
UK Local Acts UnitedKingdomLocalAct ukla
Revised UK Local Acts UnitedKingdomLocalActRevised cukla
Acts of the Parliament of Great Britain (1707-1800) GreatBritainAct apgb
Acts of the English Parliament (1267-1706) EnglandAct aep
Acts of the Old Scottish Parliament (1424-1707) ScottishAct aosp
Acts of the Scottish Parliament ScottishAct asp
Acts of the Old Irish Parliament (1495-1800) IrelandAct aip
Acts of the Northern Ireland Parliament (1921-1972) NorthernIrelandParliamentAct apni
Measures of the Northern Ireland Assembly (1974) NorthernIrelandAssemblyMeasure mnia
Acts of the Northern Ireland Assembly NorthernIrelandAct nia
UK Church Measures UnitedKingdomChurchMeasure ukcm
Measures of the Welsh Assembly WelshAssemblyMeasure mwa
Secondary Legislation
UK Statutory Instruments UnitedKingdomStatutoryInstrument uksi
Scottish Statutory Instruments ScottishStatutoryInstrument ssi
Welsh Statutory Instruments WelshStatutoryInstrument wsi
Northern Ireland Statutory Rules NorthernIrelandStatutoryRule nisr
UK Church Instruments UnitedKingdomChurchInstrument ukci
Northern Ireland Orders in Council NorthernIrelandOrderInCouncil nisi
UK Ministerial Orders UnitedKingdomMinisterialOrder ukmo

Welsh Statutory Instruments and Northern Ireland Orders in Council follow the same numbering sequence as UK Statutory Instruments, and can therefore be legitimately referred to through a URI using either wsi/nisi or uksi. In these cases, the wsi or nisi URI is the canonical one. For example, a request to

will result in a 301 Moved Permanently response with a Location header pointing to

Legislation Years

The legislation year can be a calendar year or a regnal year. Calendar years can be used for legislation after 1963, but before that time legislation is unambiguously identified based on the year of reign of the monarch. For example:

identifies The Transport Act 1986 (c.67), and:

identifies the Sheriff Courts (Scotland) Act 1907 (c.51). If you use a calendar year prior to 1963 within a URI, you will be redirected to the canonical identifier, which uses the regnal year. For example, requesting:

will result in a 301 Moved Permanently response with a Location header pointing to

On a few occasions, a pre-1963 calendar year in a URI does not uniquely identify a particular piece of legislation. For example:

Could refer to the Friendly Societies Act 1955 (c.19) or the Air Force Act 1955 (c.19). These items of legislation have different regnal years, but the same calendar years. The above request will result in a 300 Multiple Choices response, and the result will be XHTML in the format:

<html xmlns="">
    <title>300 Multiple Choices</title>
    <h1>300 Multiple Choices</h1>
      <li><a href="/id/ukpga/Eliz2/3-4/19">Air Force Act 1955</a></li>
      <li><a href="/id/ukpga/Eliz2/4-5/19">Friendly Societies Act 1955</a></li>

Legislation Numbers

The legislation number is an integer that reflects the legislation's chapter number according to the primary numbering sequence for the type. Legislation is sometimes assigned one or more secondary numbers. Secondary numbering schemes are:

Numbering Scheme Description URI Number Prefix
Commencement and/or Appointed Day orders (C) Bring into force an Act or part of an Act. c
Legal series (L) Relate to fees or procedures in Courts in England and Wales. l
Scottish series (S) Instruments covering reserved matters applying to Scotland only, not to be confused with Scottish Statutory Instruments made under powers devolved under the Scotland Act 1998. s
Northern Ireland series (NI) Orders in Council made under section 1(3) of the Northern Ireland (Temporary Provisions) Act 1972 or paragraph 1 of Schedule 1 to the Northern Ireland Act 1974. ni
National Assembly for Wales series (W/Cy) Statutory Instruments made by the National Assembly for Wales and applying to Wales only. Such instruments will generally be made in both the English and Welsh languages. w

It's possible to use a secondary number within a URI by prefixing the number with the appropriate prefix as shown in the above table. This will result in a 301 Moved Permanently redirection to the URI using the main numbering scheme. For example, requesting

will result in a 301 Moved Permanently redirection to

Legislation Sections

You can refer to particular sections, articles, regulations and so on within a piece of legislation by appending /{divisionName}/{number} to the URI. For example, to refer to section 6 of the Road Traffic Regulation Act 1984, you can use

The name of the division that is used depends on the type of the legislation as follows:

Legislation Type Division Name
Act, Scottish Bill section
UK Bill clause
Order in Council, Order of Council or Order article
Regulations regulation
Rules rule

For example, regulation 6 of the Overseas Life Insurance Companies Regulations 2004 can be referenced with:

Further subsections can be listed after the section number, using forward slashes as separators. For example:

The numbering scheme used for the sections, subsections and so on is that used within the legislation itself.

Whole schedules can be referred to with /schedule/{numberOrLetter}, and paragraphs within schedules using /schedule/{numberOrLetter}/paragraph/{paraNumber}. For example:

Sub-paragraphs can be referred as with sub-sections described above.

In cases where a piece of legislation only has one schedule, the keyword schedule can be used on its own. For example:

To refer to other structures within a piece of legislation, such as parts, chapter and so on, the appropriate name for the structure should be used in lowercase, with separators between it and its number. Further substructures can be appended to this. For example, Part IV to Schedule 9 of the Road Traffic Regulation Act 1984 should be referenced using:

The allowed keywords here are:

Note that these are URI keywords, and always in English regardless of the language used in the legislation. However, the numbers used for parts, chapters and so on reflect the numbers used within the legislation; some legislation may contain Part II while another contains Part 2, and the URIs will reflect this difference rather than normalising on decimal numbers.

Requesting a division that does not exist within the legislation will result in a 404 Not Found response.

Document URIs

Document URIs are used to refer to particular documents on the web: versions of the legislation. Document URIs follow the template:{type}/{year}/{number}[/{section}][/{authority}][/{extent}][/{version}]

Legislation Authorities

The documents provided within the SLS API come from four possible sources, which may be reflected in the URI:

Publisher URI abbreviation Notes
Statute Law Database sld Revised versions of primary legislation; unrevised versions of secondary legislation. Revised and unrevised versions of Northern Ireland Acts and Orders in Council prior to 2006. See the description of limitations for more details.
King's or Queen's Printer of Acts of Parliament kqpap Enacted/made versions of UK legislation since 1988.
King's or Queen's Printer for Scotland kqps Enacted/made versions of Scottish legislation since 1988.
Government Printer for Northern Ireland gpni Enacted/made versions of Northern Ireland legislation since 1988.

The default authority, if one isn't given in the URI, depends on the version of the document being viewed. The revised version of legislation from the Statute Law Database will be returned for a dated or prospective version; if the enacted version of legislation is requested, you will get the King or Queen's Printer version unless it's unavailable, in which case the unrevised version from the Statute Law Database will be provided if possible.

For example:

will return the latest version of the Weights and Measures (Amendment) Act (Northern Ireland) 2000 from the Statute Law Database, which could also be accessed at the URI:


will return the enacted version of the Act from the Government Printer for Northern Ireland, which could also be accessed at:

The unrevised version of the Act from the Statute Law Database can be accessed at:

The text of this version will be the same as the Government Printer for Northern Ireland version, but may include annotations and links to other legislation.

Legislation Extents

To reference legislation as it extends to a particular country, append /{country}, where country is:

For example, to get the Rent Act 1977 as it extends to England, you would use:

It is also possible to select a section based on more than one country by listing them with a + separator. For example,

requests the versions of Section 6 of The Transport Act 1985 that are applicable to England and Scotland.

Requesting a piece of legislation, or a subsection of legislation, while specifying a country that the legislation or subsection does not extend to will result in a 404 Not Found response.

URIs that do not specify an extent are assumed to refer to the legislation as it extends to all countries.

Legislation Versions

Legislation versions fall into three general categories: enacted/made versions, dated versions and prospective versions.

Enacted/Made Versions

The enacted or made version of legislation reflects the text of the legislation when it becomes law. Primary legislation is "enacted" while the majority of secondary legislation is "made" (United Kingdom Church Instruments and Ministerial Orders are simply "created").

Using the keyword enacted, made or created at the end of a document URI provides the enacted or made version of the legislation, if such is available. The enacted version of legislation is not generally available for legislation prior to 1988.

For example, the enacted version of the Childcare Act 2006 can be found at:

Dated Versions

It is often helpful to know which parts of a piece of legislation are in force at a particular time. Often, particular sections of a piece of legislation do not come into force immediately (on the enactment date) but are brought into force later on, often through a commencement order (a particular kind of secondary legislation).

In addition, most legislation, particularly primary legislation, goes through multiple changes during its lifetime as other legislation inserts or repeals sections, paragraphs and phrases. Like the original, enacted, sections, inserted sections may not actually come into force until a separate order is made.

If no version is specified in a document URI, this is taken to refer to the version of the legislation that is currently in force. For example:

Indicates the current version of The Transport Act 1985, and will provide the most up to date version of the legislation available through the API. (This may not indicate the current state of the legislation, due to the limitations of the content available through this site.) In this case, the result will be the legislation as it stood on 1st April 2003, which is also accessible at the URI:

Any date can be used within the URI. For example:

would refer to the version of The Transport Act 1985 that was in effect on 1st June 1997.

These URIs will redirect to dates that more closely reflect the date on which a change was made. For example, the version of The Transport Act 1985 that was in effect on 1st June 1997 came into being on 19th May 1997, so the above URI redirects to

Requesting a date that is prior to the base date of 1st February 1991 will result in a redirection to the base date.

Requesting a date that was prior to the enactment of the legislation results in 404 Not Found response. And requests for sections that did not exist within a particular version will result in a 404 Not Found response, even if the section existed in a previous or a later version.

Prospective Versions

At any point in time, there may be prospective sections within or amendments to a piece of legislation: planned sections or changes that have not come into force. Using /prospective instead of a date within the URI refers to the legislation that would be in force were all prospective sections and amendments in effect. For example, Part II of the Road Traffic Regulation Act 1984 has a prospective amendment from the Railways and Transport Safety Act 2003 (sections 108 and 120) that adds a Section 22B. The prospective version of that Part would be:

Note that the URI

will currently return an 404 Not Found response, since that section does not exist in the "current" version of the legislation, whereas

will give you the relevant prospective section.

Representation URIs

Each document is available in multiple formats. The URI for a particular format follows the template:{type}/{year}/{number}[/{section}][/{authority}][/{extent}][/{version}]/data.ext

where ext is the extension for the particular format.

The format provided as the result of a particular request on a document URI is determined through content negotiation based on the mime types used in the Accept header used by the client. Available formats, their mime types and their extensions are listed on the formats page.