Drivers who break down on more than 4,500 miles of Britain's roads cannot call for help because there is no mobile phone coverage, a motoring charity has warned.

A study by the RAC Foundation found 4,561 miles of road – about 2% of the entire network – do not have any 2G coverage, the minimum needed to make a call or send a text.

These stretches of road include the A149 coast road in North Norfolk, A591 in Cumbria, A93 in Scotland and A494 in Wales.

Another 28,975 miles have partial 2G coverage, meaning only certain mobile operators provide a signal.

Motorists who rely on smartphones to access the internet for planning routes and checking for congestion could get into difficulty on 14,554 miles of road (around 6%) with a complete absence of 3G coverage, the study found.

An additional 111,679 miles – some 45% – is only covered for 3G by some operators.

In terms of 4G, more than half (56%) of the road network has no coverage, while more than a quarter (27%) has only partial coverage.

The research was based on analysis of data published by communications regulator Ofcom.

RAC Foundation director Steve Gooding said: 'There are thousands of miles of road along which you would not want to break down or have an accident because calling the RAC, the emergency services or even home wouldn't be an option.

'Even where there is partial network coverage it might not be from your network provider.

'The concepts of connected cars and drivers is at the heart of much thinking about how we might make our travelling lives easier. But the best ideas in the world will fall at the first hurdle if there are no bars on the phone.'