Getaway chaos as crash jams M25

A chemical leak from an overturned tanker paralysed a section of the M25 all day today causing the worst traffic chaos on the motorway for years.

The accident created a 12-mile rushhour jam at the worst possible time with more than 200,000 holidaymakers heading for Heathrow alone.

Traffic on the roads outside the airport was described as "horrific" and

resulted in long delays and a miserable start to the holidays for many passengers who missed flights. British Airways said they were trying to re-book "hundreds" of passengers on later planes.

Elsewhere on the motorway, the sheer volume of vehicles slowed traffic to a crawl. There was a 30-mile queue on the clockwise carriageway between

junction 24 and the Queen Elizabeth II bridge, while the anti-clockwise carriageway was gridlocked from junction five near Sevenoaks back to the Dartford Crossing.

"It's absolutely solid. This is one of the worst days on the M25 I've known," said a spokesman for AA Roadwatch. The chaos is expected to last well into tonight.

The mayhem began at 5.35am when a tanker containing a highly-combustible resin overturned on the clockwise section after colliding with a people-carrier containing five members of the same family.

The tanker driver and a four-year-old girl in the family vehicle have serious injuries but they are not thought to be life-threatening. The motorway was immediately closed in both directions between junctions 13 and 14, the exits for Egham, Staines and Heathrow. Tailbacks swiftly stretched past the A40 to the north and as far as the M3 in the south. Although one lane on each carriageway of the M25 reopened at lunchtime, police said the clockwise carriageway between junctions 13 and 14 would probably close again during the afternoon.

Firefighters tried to clear a chemical which was leaking from the tanker. Officers said the contents of the overturned tanker would have to be "decanted" into a standby tanker in a painstaking operation that was expected to last into the evening.

A Surrey police spokeswoman said: "Traffic is being diverted on to surrounding roads. It's chaos out there."

Huge traffic queues rapidly built up around west London. Within an hour of the crash there were more than 12 miles of stationary traffic on the M25 with the M40, M4, M3 and other roads badly affected.

On the anti-clockwise carriageway traffic backed up eight miles beyond junction 16 with the M40. To the south, the clockwise carriageway was solid for four miles back to junction 12 with the M3.

Inspector Sue Lampard of Surrey police said: "It couldn't happen at a worse time, the beginning of the rush hour and start of the holiday season."

Many motorists trapped in the chaos were bound for Heathrow and Gatwick.

Office manager Nicola Russell, 33, had presented her boyfriend Spencer Walker-Hebborn with a surprise gift of a flight to Paris to celebrate his 33rd birthday today.

But the traffic chaos turned the one-hour journey from their homes in Thurrock into a fourhour one. Mr Walker-Hebborn said: "We left about 6.20am and faced immense delays. It was horrendous, waiting in the car knowing we would miss our flight."

Miss Russell said: "I gave him the tickets at one minute past midnight last night as a surprise present for his birthday. It's meant to be a romantic weekend break but now we're stuck at the airport."

Airport engineer Alistair Jack, 27, said: "I will have to stick it out because I have to get in anyway."

Many airlines arranged for passengers who missed their flights to travel on the next available plane at no extra cost.

A BA spokeswoman said: "Hundreds of passengers have been affected and we are doing all we can for them. We are rebooking them onto later services."

Additional reporting: Laura Burkin, Patrick McGowan, Richard Allen, Danielle Demetriou and Martin Delgado.