Traffic is being diverted via the hollow square symbol on road signs

Exit at J25 of the M25At the roundabout take the first exit on to the A10 southbound

Continue on the A10 to the Great Cambridge Junction with the A406 North Circular

Follow the A406 North Circular westbound to the junction with the A1

Turn right on the A1 northbound

Remain on the A1 northbound to J23 of the M25

At the roundabout take the first exit to re-join the M25 anti-clockwise