That is double the depth previously deemed worthy of being filled in by Lancashire County Council's highways bosses.

Residents and commuters accused the council of trying to save money at the expense of safety.

Graham Sowden, 36, from Wesham, near Kirkham, drives into Preston to work in Marsh Lane.

He said: "It is just another council gimmick to save money and there is always a way of not paying out.

"It is not too bad at 2cm, but 4cm could be bad."

Cyclist Marian Singleton, 54, of Woodplumpton Road, Woodplumpton, near Preston, said: "Being a cyclist, you have to keep as close as possible to the pavement, but it is difficult because of the potholes."

But County Coun Matthew Tomlinson, cabinet member for environment and transportation, denied the change was a money-saving move.

He said: "I would strongly refute that we are doing it to save money.

"We are convinced, in the light of appropriate risk assessment, that 4cm is an appropriate level at which to intervene.

"It was felt 2cm was acceptable and it didn't cause any increase in risk to users of the highway. We can't afford to keep the roads and footpaths perfect but we will keep them safe. Safety will be our number one priority."

Following the changes, which came into force last year, repairs will continue to be carried out on 2cm deep potholes where the damage might affect pedestrians crossing the road, such as at a dropped kerb or a crossing.

On all other roads, when the damage reaches 4cm deep, repairs must be carried out within 24 hours.

Busy pathways will still be repaired within 24 hours if they have 2cm of damage, while rural roads are only dealt with when the damage gets to 10cm deep.

It costs around £200 to fill in an average pothole, but the price is nearer £20 if it is done as part of general resurfacing.

Utility firms have carved up miles of Lancashire highway over recent months, with 11,000 notices of work on Preston's roads received by highways officials in just nine months.

From Tuesday councils can clamp down on disruptive street works.

Gas, electric and water companies will have to apply for a permit before starting work.

The county council repairs around 30,000 defects, including potholes and uneven flags, every year.

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