The M25 has been closed in both directions in Hertfordshire as police deal with an ongoing incident, with motorists warned to expect significant delays.

National Highways confirmed the motorway is shut between Junction 21A at Bricket Wood and Junction 22 at London Colney, near St Albans.

Hertfordshire Police are managing the incident, while National Highways Traffic Officers are assisting with traffic management.

The nature of the incident has not been disclosed, and there is currently no estimated time for the motorway to reopen.

Diversions in place

Drivers travelling clockwise towards Harlow are being diverted off the M25 at Junction 21A, following the A405 towards St Albans before joining the A414 and A1081 to rejoin the motorway at Junction 22.

Anti-clockwise traffic heading towards Heathrow is being diverted from Junction 22 via the A1081, A414 and A405 before rejoining the M25 at Junction 21A.

Both diversion routes are marked by hollow square symbols on roadside signs.

National Highways is advising motorists to allow additional travelling time, consider alternative routes or delay their journeys where possible.

The closure is expected to cause disruption to traffic travelling around the northern section of the M25, including journeys towards the M1 and surrounding Hertfordshire road network.

Motorists can obtain further updates from National Highways on 0300 123 5000.

The circumstances of the police incident remain unclear.

For Google News, I’d use: “M25 closed in both directions between J21A and J22 as police deal with ongoing incident.”