Question to the Department for Transport:

To ask the Secretary of State for Transport, how many London boroughs have implemented a 20 mph speed limit; how many attempted prosecutions there have been for exceeding such speed limits in each of the last five years; and how many such prosecutions have resulted in a conviction.

The figure for the number of London boroughs who have implemented 20mph speed limits is not held by the Department for Transport.

The Ministry of Justice do not hold data breakdown by local authority or the number of attempted prosecutions. However, they do hold data on the number of defendants proceeded against at court, prosecuted and sentenced for speeding offences; this data can be viewed on the Ministry of Justice website, at the following link:

https://www.gov.uk/government/statistics/criminal-justice-system-statistics-quarterly-december-2014

In the link to “Motoring data tool with criminal justice area” – you will find a pivot table which contains data on court proceedings for motoring offences, including speed limit offences, in England and Wales for the 12 months ending December 2004 to 12 months ending December 2014.