Whilst, as the Office of Tax Simplification have noted, longer legislation 'can be clearer and easier to use' (p. 2), the length of the UK's tax legislation is often used as an indicator of the complexity of the country's tax regime. Below, we consider two of the most popular methods through which this length — and its changes over time — can be (approximately) measured.

Perhaps the most common proxy measure of the total extent of UK tax legislation in any given year is the combined length of that year's Yellow and Orange Tax Handbooks. The Handbooks have been published annually since 1976, and the Library holds a copy of every edition.

Each edition of the Yellow Handbook reproduces the fully amended text of all of the direct tax legislation in force in the UK at the date of publication, whilst the Orange Handbook does the same for indirect tax. Taken together, therefore, the Handbooks have some merit as rough indicators of the total length of the UK tax code at particular points in time.

That said, there are a number of caveats that one ought to be aware of when using them for this purpose:

• Not all of the material included in the Handbooks is current legislation, or indeed statutory material at all. Both books are liable to include additional material such as editors' footnotes, repealed and revoked legislation, statements of practice, interpretations, press releases, and index pages — though the range and volume of such material has changed over time. In a report published in 2012 (p.14), the Office of Tax Simplification estimated that only around 34.3% (or about 6,102 pages) of the 2010-11 Handbooks is taken up by actual substantive UK tax legislation.
• Certain editions include statutes which have tax-related ramifications, but which are not strictly tax legislation. Some reproduce statutes on employment, for instance.
• Material is sometimes duplicated within a single edition. For example, identical extracts from certain statutes may appear in more than one volume.
• Some editions include EU legislation which may not necessarily have been incorporated into UK law. This is the case for the 2023-24 edition, for example.
• There have been occasional changes to page layouts, page sizes, and font sizes. In 2010, for instance, the amount of space around some of the headings was reduced slightly.
• The date at which the legislation was compiled varies from year-to-year. For instance, the 1976-77 Handbooks give the law as operative at 6 August 1976, whereas the 1996-97 editions set out the Acts as operative at 29 April 1996.

By way of an indicative illustration, figures on the length of the Handbooks for 1976-77, 1986-87, 1996-97, 2006-07, and 2016-17 onwards are set out below — first in the form of a chart, and then in a table. These figures ought to be considered in light of the caveats outlined above.

Year	Number of pages — Yellow	Number of pages — Orange	Total number of pages
1976-77	1,111	515	1,626
1986-87	1,669	1,221	2,890
1996-97	4,750*	2,500*	7,250*
2006-07	9,742	2,922	12,664
2016-17	16,891	7,090	23,981
2017-18	17,633	7,599	25,232
2018-19	18,016	6,985	25,001
2019-20	18,129	7,027	25,156
2020-21	14,657	6,179	20,836
2021-22	15,224	6,733	21,957
2022-23	15,461	6,803	22,264
2023-24	15,961	6,769	22,730
2024-25	16,326	6,859	23,185

Another (partial) indicator as to the fluctuating extent of legislative intervention in the tax regime is the length of published Finance Acts.

Please see below for a graph showing figures on the number of sections, schedules and pages contained in all Finance Acts passed since 1940, by year.

The bar chart below, meanwhile, provides data on the total number of Finance Act pages and the average number of Finance Act pages per year for each five-year period since 1940.