Collision investigators were at the scene of a serious crash on a dual carriageway.

The A405 was closed in both directions in Bricket Wood for more than nine hours - with the road first shutting at around 7am.

Police have not revealed any further details about today's collision apart from this morning when the force tweeted it was in the attendance of a 'serious' crash.

The crash involved a white Mercedes which ended up on its roof.

Next to the Mercedes, a forensic tent was erected in lane two, close to the central reservation.

Virtually nothing was left of the front of the vehicle and the engine could be seen lying in the road.

Just before the crash scene, a cordon was in place near a footbridge which runs over the A405.

There was clear visible damage to the stairwell of the bridge.St Albans & Harpenden Review:

Cordon near the footbridge

The crash happened on the A405 travelling in the direction of the M1.

But police shut the dual carriageway both ways between the M1 and M25, with collision investigators on scene.

However the A405 has now re-opened - Highways England tweeted at 5.20pm the closure had been lifted.

This is roughly where the overturned Mercedes has come to a halt. 

St Albans & Harpenden Review:

Drivers are turned away from the scene near the M1. Two fire engines are parked up alongside a police car. However, the crash scene is on the A405 behind where this photo is taken.

St Albans & Harpenden Review:

A highways truck in the distance blocks off the A405 at the junction with the M25

St Albans & Harpenden Review:

Looking towards the crash scene which is out of shot

During the closure, a collision van was parked up close to the Mercedes.

Police cordons were also in place along Old Watford Road.

This morning, Herts Police tweeted: "Due to a serious RTC, the #A405 is currently closed in both directions between Jct 21A M25 and Jct 6 M1 #BricketWood.

"Closures likely to be in place for some time. Please find an alternative route."

No further updates have been released by the police.

It's unknown how many people were travelling in the Mercedes. There was no sign of any other vehicle at the scene.

A lot of drivers were using How Wood, Park Street, and Bricket Wood to bypass the closure and these routes were busy throughout the day.

Narrow Lye Lane, off the A405 near Chiswell Green, also become gridlocked.