Road safety campaigners are blaming a cut in traffic police for a 40% in the number of motorists caught using mobile phones while driving between 2011-12 and 2015-16.

According to a Freedom of Information request by the BBC, 177,900 people were stopped in 2011-12 by police, compared with 93,606 in 2015-16.

At the same time, there has been a 23% reduction in the number of traffic officers, from 5635 in 2010 to 4356 in 2014, according to the Police Federation.

Data from the FoI found that 21 forces have seen their conviction rates drop by more than half and just two police forces have seen the number of people caught increase in that period.

Road safety charity Brake called for an “urgent investment” in road policing following the publication of data.

“As our police forces have faced major budget reductions, road traffic officers have too often been seen as a soft option for cuts; they are an essential part of the service and save lives,” said Alice Bailey, communications and campaigns advisor at Brake.  “As the Government brings in tougher new penalties for this crime it must make sure it resources our police forces properly so this is a real deterrent.”