Road closures have been put in place under a railway bridge after it was damaged.

Motorists must take a diversion of just over three miles while works are underway in Hunton Bridge Hill, below the train tracks, to fix damaged brickwork.

According to Hertfordshire County Council, the closures began at 10pm last night (September 2) and are set to continue until 6am on September 7.

It was initially shared that it was a series of overnight closures but the carriageway has been blocked during the day today. Update: It has been confirmed that the works are only taking place overnight but the road closure is in place 24/7.

It is a planned closure, rather than as a response to an emergency need for repairs, and is being put in place to replace damaged brickwork around the edge of the underpass.

Chevrons facing out onto the road are also set to be replaced, Hertfordshire County Council added.

The bridge in Hunton Bridge Hill last night. (Image: Chris Whately-Smith/Watford Observer Camera Club)

Network Rail is carrying out the repairs, as they are for “rail purposes”.

The government body has been contacted for more information on the nature of the damage but pictures show that several bricks by a missing section of chevrons in the top left corner on one side are missing.

Update: Network Rail has said the damage was the result of a "bridge strike at some point last year". It appeared optimistic that the bridge could be reopened soon.

A diversion route sends motorists 3.20 miles around Old Mill Road, the A41, onto Aerodrome Way, Tibbs Hill Road, and then South Way.

The bridge in Hunton Bridge Hill last night. (Image: Chris Whately-Smith/Watford Observer Camera Club)