The M1 has fully reopened after a crash involving five cars and a lorry closed the northbound carriageway this morning.
No-one was seriously hurt in the collision, which occurred just before junction five (Watford) at about 9.30am.
Hertfordshire Constabulary said debris was spread across 100 metres of road and the carriageway was closed while emergency services cleared the scene.
Police also imposed closures on M1 access roads at Staples Corner, on the Barnet and Borehamwood border, but these have also now been lifted.
The Highways Agency says traffic is queuing on the M1 northbound but that all vehicles have now been removed from the scene.