Three men have died after their car was hit by a double decker coach on the M1 in Bedfordshire.
They were parked on the hard shoulder between junction 12 and 13 on the northbound section of the motorway when the crash happened at 6.45am on Saturday, police said.
The accident came an hour before another fatal collision on the M40 in Oxfordshire, when at least one person died in a 30 car pile-up.
The M1 was closed northbound after the crash but all lanes have now re-opened and delays have cleared.
A spokesperson for Bedfordshire Police said: "Three men in the car were pronounced dead at the scene and a fourth man was taken to the John Radcliffe Hospital, Oxford, with serious injuries.
"No one in the coach, which was travelling from Kent, was hurt."
Two of the men who died and the man who survived were from Buckinghamshire, police said, and the other victim was from London.
The coach driver was arrested in connection with the incident and taken to Luton Police Station, where he is being interviewed.
Police are contacting the victims' next of kin and the northbound stretch of the motorway is closed as the investigation continues. Diversions are expected to remain in place for the next few hours.
West Ham advised its fans to avoid both the M1 and M40 on their way to a match against West Brom, although police emphasised that there were no football fans on the coach involved in the crash.
There were fears that Millwall fans trying to see their team play at Leeds could also be caught up in the gridlock.
Meanwhile, two Boeing 747 fuselages were being driven along the M4 and M5, causing delays and congestion.
Anyone who witnessed the collision is asked to contact Bedfordshire Police on 101 or Crimestoppers, anonymously on 0800 555 111.
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