Motorists travelling on the M1 near St Albans district have been warned to expect traffic delays into the evening following a two-car collision, which resulted in a man being airlifted to hospital.

A spokeswoman for Herts Police said that a silver Honda Accord collided with a Mazda MX-5 at about 2.50pm while travelling southbound, between junctions 7-8, near Hemel Hempstead.

One of the cars overturned and traffic was brought to a standstill.

Both carriageways had to be closed to allow for the landing of an air ambulance on the motorway.

A spokeswoman for the East of England Ambulance Service NHS Trust said that an ambulance officer arrived at the scene within seven minutes of an emergency call to paramedics.

That officer was then joined by a rapid response vehicle, ambulance and the Herts Air Ambulance.

A man in his 40s was airlifted to the Royal London Hospital in a serious but stable condition.

The northbound carriageway was reopened at 3.50pm and two southbound lanes have also recently been reopened, but there are still tailbacks on the motorway.

According to the Highways Agency website there are 30-minute-long delays due to congestion as a result of the accident.