TRAFFIC on major routes through the region will be restricted to single lanes this week while essential work is carried out on four bridges.

The bridges are Barton North and South and Clow Beck, on the A1(M) in North Yorkshire, and the Blackwell Spur Bridge, on the A1(M)/A66(M) interchange, near Darlington.

Cracking has been discovered in some of the gully covers in the hard shoulder of the motorway, which traffic had been using during previous roadworks.

Delays are expected at peak times, but northbound traffic can divert via the A168 and A19.

It is anticipated that the work on replacing the covers will be completed by Monday.

Andrew Jennings, of the Highways Agency, said: "We do apologise for the inconvenience that this may cause to drivers over the next few days.

"It is important, however, that we replace these covers to ensure the continued safety of road-users."

The bridges are currently undergoing £2.4m worth of improvement works.

The two Barton Bridges will have parapets replaced, while the bridge deck on the Blackwell Spur will be extended.

Blackwell Spur Bridge will also have substantial concrete repair work carried out, as well as re-painting and parapet-replacement work.

Clow Beck Bridge will be slightly modified and also have repairs to the bridge pier carried out.