A man has been injured in a crash between two vehicles on the airfield at Heathrow Airport.
Two members of staff driving vehicles were involved in the collision on the taxiway just after 06:00 GMT.
One man, aged in his 40s, was taken to a west London hospital. Another man was treated at the scene.
Heathrow said it was not expecting an impact on journeys but some passengers reported delays on the tarmac and at their gates.
Alastair MacLeod tweeted: “Apparently there has been an accident on one of the runways at @HeathrowAirport and many planes (including this one) are parked on the apron with unspecified delays of ‘hours’. No public news of this and no useful updates from @British-Airways – anyone out there know any more?”
Another passenger said: “There’s only one airport in the world that can turn a 1hr early landing into a delay at gate. @HeathrowAirport thanks for nothing.”
The Health and Safety Executive has been informed and there has been no arrests, the Met Police said.
Heathrow said the the airfield remained open and it was “working to minimise disruption to passengers’ journeys.”
“This incident did not involve any passengers and is not expected to cause any impact on journeys today”, it added.