A BRIDGE approaching its 200th birthday on a busy main road near Northallerton is being strengthened against the weather, juggernaut lorries and careless motorists who crash into its ancient parapets.

The estimated £160,000 being spent on Morton-on-Swale bridge might seem insignificant compared with the sum swallowed up over six months by one of its badly-damaged counterparts over the same river at Richmond.

But the investment is seen as an insurance policy for the future by North Yorkshire County Council, which has given Morton-on-Swale a high priority on its county-wide list of bridges needing strengthening or repair. In some cases away from main roads, weight and width limits have had to be placed on weak bridges.

Traffic lights are expected to remain in place for at least five weeks while work continues on the bridge, a listed structure designed by John Carr and built in 1803. The four-arch bridge carries an estimated 12,000 vehicles a day, many of them heavy lorries of up to 42 tonnes, along the A684 between Northallerton, Leeming Bar, Bedale and the dales and lakes.

A county council spokesman said: "The bridge is very much exposed to the elements and has suffered severe erosion because of weathering to the stonework and the effects of salt.

"The parapets have been particularly affected and have significantly deteriorated.

"The bridge is on an angle and some drivers have been unable to keep their cars on the road and have struck the parapets.

"We are concerned that, as it stands, the bridge is not sufficiently strong to prevent vehicles from just going through the parapets.

"The road on which the bridge stands is also a main link between the A1 and A19 for a good number of HGVs."

The spokesman said stone which was as close a match as possible to the original was being specially imported by contractors from a quarry in Northumberland.

He added: "We are apologising for any inconvenience caused by traffic lights on such a busy road, but this is a critical structure."

l An ancient river crossing in Nidderdale is having to close to traffic after it was damaged by a lorry - and now council officials are trying to trace the culprit in a bid to present the driver with a £2,000 repair bill.

The single carriageway bridge at Hampsthwaite, near Harrogate, which is listed, has had its stone parapet damaged.

North Yorkshire County Council highway officials believe the lorry was too big to cross the bridge, which is legally limited to vehicles up to 6ft 6in wide. If the driver is not traced, council taxpayers will have to pick up the bill.

County assistant divisional enginer Mr Alan Jobling said the council was trying to trace the culprit, but pleaded with anyone with information to contact police.

Scaffolding will have to be erected on the riverside to repair a 2in-wide crack down the side of the bridge. Work is also needed to put back into place stones moved by the impact.

The bridge links Hampsthwiate with Clint Banks across the River Nidd. Once repair work starts a diversion will be set up via Birstwith.