An air ambulance has been called after a multi-vehicle crash left several people trapped and injured.

Emergency services were called to the A41 between Kings Langley and Hemel Hempstead approaching the M25 at around 10.11am today (August 21).

Herts Police confirmed officers are currently on the scene alongside ambulance crews and the fire service after a crash involving “multiple vehicles”. It is currently unclear exactly how many.

“Road closures are in place and motorists are urged to avoid the area where possible, and long delays are expected,” a force spokesperson added.

Herts Fire and Rescue Service added: “Firefighters are working to release several injured people from vehicles and assisting the ambulance service with casualty care."

Update: Lorries involved in 'gruesome' A41 crash

There are delays of nearly 40 minutes, according to Google Maps, with heavy congestion along the A41 and A4251 approaching the M25.

An East of England Ambulance Service spokesperson said: "We received a call at 10.17am with reports of a collision on the A41, Kings Langley.

"We have a number of resources at the scene where crews are assessing patients."

It is currently unclear how many people have been injured. For the latest updates see our live blog here.