A £1.1m scheme to replace and improve the road surface of the A1 between Biggleswade and St Neots will start on Monday, July 21.

The work, which takes place overnight on weekdays from 8pm to 6am, will also include repair works to Tempsford Bridge over the River Great Ouse.

The aim is to improve the road condition and reduce noise levels over 7.5 miles on both carriageways.

Clearly-signed diversion routes will be in place.

There will be no work over the August bank holiday weekend (Friday, August 22 until Tuesday, August 26) and the work is due to be completed by late August.

Highways Agency Project Manager Nick Cook said:

"We are doing this work at night when the traffic flow is less to reduce delays to drivers. We are also carrying out repair work to Tempsford Bridge at the same time as improving the A1 carriageway to help motorists make their journeys safely and reliably."

The work will be carried out in four phases:

* Monday, July 21 to Saturday 26 July: Overnight closure of the northbound carriageway between the Biggleswade north roundabout and Sandy roundabout.

* Monday, July 28 to Saturday, August 2: Overnight closure of the northbound carriageway between Sandy roundabout and the Black Cat roundabout.

* Monday, August 4 to Tuesday, August 19: Overnight closure of the southbound carriageway between the Black Cat and Sandy roundabouts.

* Tuesday, August 19 to Saturday, August 30: Overnight closure of the A1 southbound between the Sandy and Biggleswade north roundabouts.

The diversion route for the northbound closure between Biggleswade north and Sandy roundabouts, and the northbound closure between Sandy and Black Cat roundabouts, is as follows:

Traffic wishing to travel northbound on the A1 will exit the A1(M) at junction 10 for Baldock, onto the A507 westbound to Clophill roundabout. Motorists will then join the A6 northbound to the A421 roundabout at Elstow and then onto the A421 eastbound to rejoin the A1 at Black Cat roundabout.

When the A1 southbound is closed, traffic will follow the same diversion route in the opposite direction. Local access will be maintained.

The scheme is being carried out by Tarmac, Link Line and EMDD, supervised by Carillion-URS on behalf of the Highways Agency.