An air ambulance landed on the M25 after a "serious collision" this evening (Wednesday September 22).

The crash involving a motorbike and car happened at junction 17 near Maple Cross, National Highways has said.

It occurred on the clockwise carriageway between the slip roads at junction 17 at around 4.20pm, police said.

Police, paramedics, and traffic officers were in attendance. An air ambulance landed at around 5pm, which temporarily closed the M25 in both directions.

The rider of the Yamaha bike was flown to hospital with serious injuries, with the motorway fully reopened at around 7.30pm.

Hertfordshire Constabulary has launched an appeal for witnesses and dash cam footage.

Sergeant James Wood, from the Bedfordshire, Cambridgeshire and Hertfordshire (BCH) Road Policing Unit, said: "We are particularly looking for dash cam footage of the vehicles involved to establish the circumstances around the collision.

"As part of this, we are appealing for any witnesses to come forward. Did you see the collision itself or capture footage travelling towards Watford at around this time? If you can help, please contact us."

Anyone with information is asked to email james.wood@herts.police.uk pr call 101 quoting ISR of September o22.

The M25 has reopened in both directions. There were delays anti-clockwise back to the M1 at junction 21 while traffic queued clockwise from junction 15 for the M4, causing journey times of around 90 minutes. 

Away from the M25, roads in and around Maple Cross, Rickmansworth, Chorleywood, and Denham were affected as drivers avoided the M25.