A pair of M25 closures near Watford have been added to the latest two-week look ahead for M1 and M25 works.

Motorists will have to take a diversion down smaller roads - adding up to half an hour to journeys - when the clockwise M25 is shut overnight between junction 19 and junction 21a. Closures will be in place from 10pm and 5am between September 11 and September 13, while maintenance works are carried out.

The motorway will also be shut clockwise overnight, from junction 22 to junction 23, between September 16 and September 21. This is for surfacing works, starting from 10pm and with a closure lasting until 6am each morning.

The diversion is similarly expected to cause delays of up to 30 minutes for journeys.

M1:

  • From 10pm September 4 to 5am September 5: Slight delays (under 10 minutes). Northbound, junction 4 to junction 6. Lane closures for maintenance works.
  • From 10pm September 4 to 5am September 5: Slight delays (under 10 minutes). Northbound, junction 6 to junction 4. Lane closures for maintenance works.
  • From 10pm September 5 to 5am September 6. Slight delays (under 10 minutes). Southbound, junction 5 to junction 4. Lane closure for parapet replacements.
  • From 11pm September 6 to 6am September 7. Slight delays (under 10 minutes). Northbound, junction 4 to junction 5. Lane closure for parapet replacement works.

M25:

  • (In progress) From 10pm September 2 to 5.30am September 28: Moderate delays (10-30 minutes). Clockwise, junction 23 to junction 24. Lane and slip road closure for NEAR Scheme, diversion via National Highways roads.
  • From 10pm September 11 to 5am September 13. Moderate delays (10-30 minutes). Clockwise, junction 19 to junction 21A. Lane closures, slip road closures and carriageway closure for maintenance works. Diversion via local authority roads.
  • From10pm September 16 to 6am September 21. Moderate delays (10-30 minutes): Clockwise, junction 22 to junction 23. Lane closures, slip road closure and carriageway closure for surfacing works. Diversion via local authority and National Highways roads.

A1(M):

  • (In progress) From 9pm August 15 to 5am September 12: Moderate delays (10-30 minutes). Southbound, junction 2 to A1 southbound junction with Rowley Lane. Lane closure for urgent bridge repairs.
  • (In progress) From 10pm September 3 to 6am September 7. Moderate delays (10-30 minutes). A1(M), M25 and A1 northbound, southbound, clockwise and Anticlockwise, junction 24 to junction 23 and junction Bignells corner. Lane, slip road, and roundabout closure for surfacing works. Diversion via National Highways roads.