Both directions are currently shut between junction 22 (St Albans) and junction 21A due to a major blaze at a commercial building near the motorway. Smoke and debris have affected the carriageway, raising concerns about potential explosions and forcing the closure as a precaution. Alternative routes for M25 driversDrivers travelling clockwise should leave the M25 at Junction 21A and follow the Hollow Square diversion via the A405 towards St Albans, A414 towards Hatfield and A1081, before rejoining the M25 at Junction 22 towards Harlow. Drivers travelling anti-clockwise should leave at Junction 22 and follow the Hollow Square diversion via the A1081 towards St Albans, A414 towards Hemel Hempstead and A405 towards Watford. Traffic can then rejoin the M25 at Junction 21A towards Heathrow.