The bomb squad is dealing with a “suspicious” package found beneath a motorway bridge on the M1 which has caused five-Mile tailbacks.
Thames Valley Police said it was called to “reports of a suspicious object” underneath a motorway bridge between junction 15 for Northampton and junction 14 for Milton Keynes around 7.30am.
A spokesperson told HuffPost UK that the situation was ongoing and declined to comment on reports that the package had been detonated.
Pictures of social media however show the bomb squad in attendance while bored motorists have been videoed playing football and riding a skateboard amid the queues.
Buckinghamshire Fire and Rescue Service crews are also in attendance amid reports that traffic is backed up for five miles.
The M1 is closed in both directions between junctions 14 and 15 and diversions are in place in place in both Milton Keynes and Northamptonshire.
Police said the road closures are likely to be in place for “some time” while officers and the fire service investigate the matter.
The force has advised motorists to avoid the area.
Stuart Paterson reported hearing the bang and earlier wrote on Twitter that motorists were getting out of their vehicles.
Another Twitter user claimed to have seen a “black bag smoking and oozing yellow stuff”.
Former England cricketer James Taylor, who was stuck in the tailback, posted a video of a man skateboarding along the deserted motorway.
National Express says 45 minutes is being added to travel times and coaches are being diverted from the area, amid several miles of tailbacks.
Buckinghamshire Fire and Rescue Service has said: “Firefighters are assisting Thames Valley Police with their investigation into a report of a suspicious object found underneath a motorway bridge, M1 southbound between junctions 15 (Northampton) and 14 (Milton Keynes).
“One appliance and crew from Newport Pagnell, one from Broughton, one from Great Holm, the Environmental Protection Unit from Aylesbury and two officers are attending.”