Companies could be charged £500 a day "lane rental" for digging up roads under a project aimed at easing congestion.

The trial, unveiled in Camden, north London, yesterday, could lead to electricity, gas, water and cable firms being penalised by the day for road work disruption, which is estimated to cost businesses £2bn a year. The revenue from the charges, also piloted in Middlesbrough, will be kept by councils to fund road improvements.

But the utilities are claiming they are being scapegoated because councils, which oversee many roadworks, are exempt from the proposals.

In London, about 500,000 holes are dug by the utilities annually; Camden alone has 20,000 sets of roadworks.

John Spellar, the transport minister, said the schemes and the rules allowing highway authorities to charge companies £2,000 for each day they overran deadlines, were a radical approach.