The northbound carriageway has been shut between junctions 11A and 12 near Luton and Dunstable. The closure is impacting people trying to get to Luton Airport.
Highways England tweeted: “M1 Northbound J11A to J12 , if you are caught within the trapped traffic, we are looking to move you as quickly as possible.
“Please DO NOT move your vehicle unless told to do so by our Officers.”
The diversion sees motorists forced to leave at junction 11a and follow a different route.
The route is marked with a yellow square towards the A5 Northern Dunstable Bypass.
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Drivers should then take the third exit towards the B5120.
Traffic will then be taken back to the M1 via junction 12.
Highways England said a collision investigation is required and the road will stay shut for a “protracted amount of time.”
It comes as Several vehicles were involved in a collision between junctions 36 and 37 earlier this month, according to Highways England.
The motorway agency said emergency services were at the scene and traffic was being held.
Highways England said on Twitter: “We have been made aware of a multiple vehicle traffic collision just south of J37.
“Lane 3 and 2 closure is being established with traffic officers just on scene. Heavy congestion on approach.”