The Highways Agency has revised the rules on potholes in the road. Previously contractors were required to ensure that drivers were given a quiet, comfortable and even ride by making sure that any defects in the surface of the road were repaired within a 24-hour timeframe.

However, the new rules state that potholes smaller than 15cm wide or 4cm deep are not classed as urgent for repair. The new guidelines refer to trunk roads and motorways.

The massive increase in potholes is a consequence of three severe winters with 2010/ 2011 being the coldest for 100 years combining with years of underinvestment in routine road maintenance.

IAM director of policy Neil Greig said: “This just seems to be storing up larger repair bills for the future. All large potholes start off as small potholes -- it’s easier and cheaper to fix them early and reduce the risk to road users.

“The reaction of the Highways Agency to this crisis is worrying because it seems to be an attempt to switch their legal responsibilities to maintain safe motorways and trunk roads from themselves to their contractors, in the hope they will come up with something.

“The Highways Agency's roads are the backbone of the country's transport system which is why the IAM would like to see their risk assessment of this decision to be assured that motorists will not be put at risk.”