Update: M1 blocked due to serious multi-vehicle accident to reopen

Two lanes (of four) are now open on the M1 southbound between J29 and J28.

There are long delays on approach, so allow extra time for your journey should you be travelling in the area.

Highways England have tweeted: “All trapped traffic has now been released and the scene is clear on the #M1 southbound between J29 and J28. We will now start the process of reopening the carriageway and slip roads. Traffic has now been stopped just prior to J29 exit slip road to allow this to begin.”

The incident - in which one car has overturned - happened at around 2pm.

The northbound carriageway was also closed for a time but this has now been reopened. An air ambulance has attended the scene in order to relay a casualty to hospital. The fire, police and ambulance services are all also currently at the scene as well as the Highways Agency.

Motorists are being advised to consider alternative routes. Drivers caught up in the traffic should follow the hollow square diversion symbol.

More on this story will follow as and when we get it