Workers on a bridge replacement project in Hackbridge, which has been causing traffic disruption for nearly a year, are being pelted with rubbish by angry motorists.

Project manager Alan Carroll said motorists have thrown cans of drink at workers, sprayed them with ketchup and even used catapults to fire ball bearings at them. He said he thought the actions were taken by a mixture of frustrated motorists and irresponsible pranksters.

The project to replace the 150-year-old London Road bridge began in November 2009. Although the road has remained open during most of the project, the reduction to single lane traffic has led to tailbacks.

Mr Carroll said: “When the bridge was originally built the only traffic on it was horse and cart.

“If we allowed the bridge to continue to deteriorate then, at some stage in the future, it wouldn't have been able to take the weight of traffic and would probably have ended up being closed completely.

“When it is finished, the bridge will be good for another 120 years.”

The new bridge, which will also provide new cycle lanes and wider pedestrian footpaths, is due to be completed by Christmas Eve.

Mr Carroll is pleading with motorists to be patient after a number of motorists have also been seen racing through the red lights, running the risk of a collision with cars coming from the other direction.

Mr Carroll said: “We have been taking the licence plate numbers of anyone we see jumping the lights.

“As well as the risk of a fatal collision, jumping the lights can actually mean it takes longer to get across with motorists having to reverse slowly back over the bridge.”

Mr Carroll warns there will be several more necessary road closures before the £4m project is completed.

The road will be closed from 11pm on Saturday, October 2 to 6am on Sunday October 3, from 11pm on Saturday, October 9 to 6am on Sunday, October 10 and from 11pm Friday, October 22 to 6am on Monday, October 25.

Councillor Simon Wales, executive member for communities, transport and voluntary sector, said: “I would like to apologise to residents and motorists for any disruption this essential work will cause.

“This new bridge will greatly improve access to Hackbridge for vehicles and will have wider pavements which will make the bridge safer for pedestrians.

“Every effort has been made to keep the bridge open during construction but unfortunately some planned closures are needed.”