Motorists are stuck in queues more than 12-miles long after three lanes were closed on the M25 because of a protest.
Drivers are stuck in long queues after three lanes were closed on the M25 because of a protest held by a fathers' rights activist dressed as Batman.
The protester, believed to be an activist from Fathers 4 Justice, climbed on to a gantry about a quarter of a mile before junction 14.
Geoffrey Hibbert, 48, of Farnborough in Hampshire, is perched on a gantry about a quarter of a mile before junction 14.
The anti-clockwise carriageway between junction 15 and junction 14 has been closed, affecting traffic bound for Heathrow Terminals 4 and 5.
The Fathers 4 Justice campaigner said he was prepared to protest all day.
The Highways Agency warned drivers to expect delays of up to 90 minutes.
The anti-clockwise lanes, between junctions 15 and 14, have now been reopened to traffic. A portion of the slipway remains cordoned off.
The slow-moving traffic is affecting drivers and the tailback now stretches as far back as junction 18 at Chorleywood in Hertfordshire.
'Absolutely stationary'
The protester, 48-year-old Geoffrey Hibbert, from Farnborough in Hampshire, who is dressed as Batman, told the BBC: "I'm doing this for my daughter. I'll do my protest all day."
The earlier closure of the carriageway resulted in tailbacks as long as 15 miles (24km), which affected traffic bound for Heathrow Terminals 4 and 5.
The Highways Agency said traffic was queuing as far back as junction 18 at Chorleywood in Hertfordshire, and warned drivers to expect delays of up to 90 minutes.
Speaking by mobile telephone, Mr Hibbert told the BBC: "I'm doing this for my daughter. I'll do my protest all day."
Chris Connor, from Buckinghamshire, was caught in the traffic jam as he travelled from Fulham, west London, to Woking in Surrey.
"I was absolutely stationary for 20 to 25 minutes," he said.
"People were walking around outside their cars on the motorway."
Were you on the motorway this morning? How did the protest affect your journey?
