There is an extensive series of maintenance work planned for the A404 bridge above junction 18 of the M25 between Monday 20th March and Friday 21st April 2023. This will involve a number of different overnight closures and diversions.

See South East – Maintenance schemes – National Highways, then scroll down and expand “M25 junction 18 (A404) Rickmansworth Road bridge maintenance – Monday 20 March to Friday 21 April 2023” to see the details and schedule.