There are severe delays on the roads tonight.

Traffic is solid on the A1 southbound from Rowley Lane down to Mill Hill Circus but it has had a huge knock-on effect on local roads.

It is unclear at this stage what has caused the traffic but it is a lot worse than your usual rush hour.

In Borehamwood, there are queues along Allum Lane towards Elstree Hill, in Shenley Road through the town centre, and on the A411 between Furzehill Road to Elstree.

Hendon Wood Lane is gridlocked in both directions between Barnet Gate and Highwood Hill.

Routes into Apex Corner are busy apart from the A41 from the direction of Edgware.

Queues on all roads surrounding Mill Hill Broadway.

Heavy traffic in Watford Way northbound between Colindeep Lane and Apex Corner.

Also expect delays near Barnet General Hospital.