Policy paper

Breath Tests

This publication was published under the 2010 to 2015 Conservative and Liberal Democrat coalition government

Introduction This section covers the use of police powers, under the Road Traffic Act 1988, to conduct roadside breath tests to determine …




This section covers the use of police powers, under the Road Traffic Act 1988, to conduct roadside breath tests to determine whether motorists are driving with alcohol in their body, beyond the prescribed limit. It examines the regional and seasonal use of such powers, as well as the number of motorists who either fail or refuse breath tests. The data presented in this chapter are drawn from returns from police forces in England and Wales and relate only to roadside breath tests (hereafter referred to as ‘breath tests’).

Further details relating to definitions, legislation and procedure are given in the User Guide.

Key facts

Police carried out 733,088 breath tests in 2010 compared to 814,207 in 2009. This ten per cent decrease followed increases in the previous two years.

The number of positive or refused tests in 2010 also decreased by ten per cent, from 93,232 in 2009 to 83,932 in 2010.

Eleven per cent of all breath tests in 2010 were refused or gave a positive result, the same proportion as in the previous 12 months.

Trend in breath tests, 2001 to 2010 

Chart notes

Source: Home Office, Breath Tests table BT.01

Data tables

Data sourced from statistical returns received from the 43 police forces in England and Wales can be found in the Breath Test tables.

Seasonal variations

Twenty per cent of all breath tests in 2010 were conducted during December, which coincides with the annual national Christmas drink and driving campaign. The number of breath tests carried out during December was almost three times more than the average number carried out in other months.

The proportion of breath tests conducted in June (14% of total tests) was also higher than in other months. This is likely to be due to police campaigns against drinking and driving during the summer months.

However, the proportions of breath tests resulting in positive readings or refused during June (7%) and December (5%), were lower than in other months (13 to 16%).

Geographical patterns

In 2010, 13 breath tests were conducted per 1,000 population across England and Wales; the rate for Wales (30 per 1,000 population) was more than twice of that for England (12 per 1,000 population). There was a big variation in the number of tests carried out per 1,000 of the population by individual police forces, from one in West Midlands to 41 in Dyfed-Powys and 43 in North Wales.

The number of breath tests per 1,000 of the population that were positive or refused averaged 1.5 throughout England and Wales, though were not as varied as the total number of breath tests by police force level. The rate of positive or refused tests ranged from 0.9 per 1,000 population in both Northumbria and Avon and Somerset to 3.3 per 1,000 population in Norfolk.

Data quality and interpreting the figures

The presented figures are correct at the time of publication. They may include revisions submitted by forces for the years covered by, and received since the publication of, Police Powers and Procedures 2009/10.

From April 2008, new digital recording equipment started to be used by forces. The devices are able to record exact breath alcohol readings and the result of individual tests, as well as reason for test, time of day, day of week and age and gender profiles of those tested, and results are downloaded to data systems on a monthly basis and provided to the Department for Transport (DFT).

Data presented here have been sourced from annual statistical returns received from the 43 police forces in England and Wales. Some of the forces’ returns for 2010 were based on the figures from the digital devices, others have supplied data from manual recording systems. Negative breath tests may previously have been under-reported to the Home Office; it is anticipated that, as more forces use data from the digital devices, this will lead to an improvement in data recording practices by forces.

The User Guide provides further details relating to data quality and interpreting the figures.

Other data sources

Analysis of reported roadside breath alcohol screening tests, based on data from digital breath testing devices, is published by the DfT. Latest figures were included within the DfT’s Reported Road Casualities in Great Britain: 2010 Annual Report.

The Association of Chief Police Officers (ACPO) publishes an annual press release showing the number of persons arrested during the Christmas drink and drug driving campaign, 1 December 2010 to 1 January 2011.