A new calculation of the politically charged figure of the proportion of UK law originating in Brussels puts it at 64.7% over the past 20 years, a business group calling for ‘fundamental’ reform said today.

The figure is much higher than the most recent official estimate of 13.3%, but lower than the 75% cited by the UK Independence Party. 

Business for Britain, which says it represents people who want ‘fundamental changes to the terms of our EU membership’, admitted that difficulties and ambiguities make calculations ‘highly subjective’. However, it said the 13.3% figure, which appears in the most recent House of Commons Library research note, is a ‘huge underestimate’ because it counts only measures that pass through the House of Commons.

Its ‘definitive’ calculation includes ‘verbatim regulation’ as well as UK legislative acts and statutory instruments implementing EU directives. Of the body of law between 1993 and 2014, EU regulations accounted for 59.3%, UK laws implementing EU directives 5.4% and UK-only legislation 35%, the study concludes. 

While the total figure includes measures with almost no impact on the UK - olive-growing legislation, for example - the laws remain in the body of UK law nevertheless.

The group said that political parties often distort calculations of the EU's influence over UK law for their own ends. ‘By making it transparent how exactly the model has been calculated, Business for Britain has tried to bring some clarity back to the debate and provide a definitive answer.’

However it admitted that ‘until EU legislation is granted the same scrutiny as UK legislation, the debate is still likely to remain unsettled’.