Work to upgrade the northern section of the M25 is continuing this month, with more overnight road closures planned.

The Highways Agency is carrying out £188million improvements to transform the motorway between junction 23 (South Mimms) and junction 27 (M11) into a “smart motorway”.

This involves converting the hard shoulder into a traffic lane, with electronic signs on roadside and overhead gantries providing information that the agency hopes will smooth traffic flows and improve journey reliability.

Work will take place overnight from 10pm to 5.30am between Mondays and Thursdays, 11pm to 6am on Fridays, and 10pm to 6am on Saturdays. No work is planned for Sunday nights.

The next overnight closures will take place on the clockwise carriageway between Monday, March 17 and Thursday, March 20. This is to allow installation of a gantry across the entire width of the highway. A divertion covering the A10, A406 and M11 will be in place.

When the gantry is lifted into place, traffic will temporarily be stopped on the anti-clockwise carriageway using a rolling roadblock.

John Martin, senior project manager at the Highways Agency said: “We will be installing overhead gantries, some of which span the entire motorway, which will provide drivers with traffic information which will improve journey reliability and reduce the likelihood of ‘stop-start’ traffic flow.