Takings at the A149 Heacham petrol forecourt and convenience store Reg J. Stainsby and Son have been cut by more than half since the beginning of works to install traffic lights at the notorious Norfolk Lavender junction.

But the situation is being made worse than it needs to be when drivers waiting in queuing traffic sit across entrances, making it impossible for customers to get in and out.

Businessman John Stainsby (70) said: "We've got these horrible roadworks doing untold damage to trade. Things are bad enough as they are without these inconsiderate drivers completely blocking off entrances.

"One account customer came in the other day and said he had been trying for three days to get in for a car wash.

"The roadworks are having a serious affect and we have got to accept those necessary blocks which are bad enough, but the unnecessary blocks are just not on. People have got to leave these lifelines open."

The roadworks, which started in December and are expected to be completed by Easter, are a bid to address safety concerns at the accident blackspot following a 20-year campaign by the parish council and locals.

The new traffic lights are intended to allow vehicles travelling from Lynn Road and Sedgeford Road to join the A149 safely and the scheme will also include improved crossing facilities for pedestrians and a reduction in the speed limit from 50mph to 40mph.

Over the past two years hundreds of people have campaigned to persuade Norfolk County Council to provide traffic-calming measures at the junction, which is renowned for crashes as frustrated motorists take chances when pulling into a stream of fast-moving traffic heading along the coast road.