Diversion routes for the second full weekend closure of the M25 have been announced, with drivers warned to only travel if "absolutely necessary".

The M25 will be shut this weekend for the second time this year, between junction 9 and junction 10, as work on the £317 million Junction 10 improvement scheme continues.

National Highways' unprecedented move of closing the motorway in March saw good progress as a bridge was demolished and a gantry installed, eight hours ahead of schedule.

The planned works now involve lifting into place concrete beams for the eastern gyratory bridge and another large gantry.

This next phase requires another full weekend closure between junctions 9 (A243 Leatherhead) and 10 (A3 Wisley) from 9pm Friday, May 10 until 6am Monday, May 13.

The diversion routes are "longer" for the second M25 closure.

Jonathan Wade, National Highways senior project manager, said: "This is far from a repeat of the previous closure, as the alternative routes are longer and will be different for over height vehicles and all other traffic.

"Drivers listened to our advice last time which reduced motorway traffic levels by over two thirds and meant delays were limited.

"Our advice again is please only travel if absolutely necessary and make sure you give yourself extra time if you do choose to use the M25."

During the closure, there will be four diversion routes depending on the direction of travel and the type of vehicle.

Each route will be clearly signposted.

Drivers using the signed diversion route will not be subject to any Ultra Low Emission Zone charges that may usually apply.

See the latest updates on the National Highways' X page @HighwaysSEAST.

Times Series: The main diversion route mapped outThe main diversion route mapped out (Image: PA Wire)

Full diversion routes for the second M25 weekend closure:

Diversion route clockwise (from Gatwick towards Heathrow) for most traffic:  

Leave the M25 at junction 8, A217 (Reigate). Follow the A217 London, Sutton, (A240) Kingston. After 3½ miles turn left onto the A240 Epsom, Kingston. After 3 miles at the Esso roundabout, turn right onto the A24 (A240) Kingston. Continue for 3 miles and turn left onto the A3 Portsmouth, Guildford. Continue for 9½ miles to the M25 and re-join the motorway at junction 10.  

Diversion route clockwise (from Gatwick towards Heathrow) for over height vehicles (over 15’0 / 4.6m): 

Leave the M25 at junction 9 A243 (Leatherhead). Follow A243 London, Hook, Chessington. After 6 miles, turn left onto the A309 Esher, Staines, (A3) Guildford, Portsmouth. After 1½ miles turn left to the A307 Esher, Guildford A3. After 4½ miles, in Cobham, turn right onto the A245 M25, Guildford A3, Weybridge, Woking. After ½ mile turn left onto the A3 Portsmouth Guildford. Continue for 1 mile and re-Join the motorway at J10. 

Diversion route anticlockwise (from Heathrow towards Gatwick) for most traffic:  

Leave the M25 at junction 10 to join the A3 towards London. After 9½ miles at the Hook interchange leave the A3 turning right onto the A240 Epsom, Reigate. Continue for 3 miles to the Esso roundabout and turn left onto the A240 Reigate. Continue for 3 miles then turn right onto the A217 Reigate, M25. After 3½ miles turn left to re-join the M25 motorway at junction 8.  

Diversion route anticlockwise (from Heathrow towards Gatwick) for over height vehicles (over 15’0 / 4.6m): 

Leave the M25 at junction 10 to join the A3 towards London. After 1 mile at the Painshill interchange leave the A3 turning right onto the A245 Cobham (A307 Esher). After ½ mile turn left onto the A307 Esher. Continue for 4½ miles then turn right onto the A309 London, Sutton. Continue for a further 2 miles to the Hook interchange and turn right onto the A243 Dorking. After 6 miles, turn left to re-join the M25 motorway at junction 9.