It was "truly miraculous" that no one was killed in a 100-car pile-up on a bridge in heavy fog, police have said.

Eight people were seriously injured and 35 are in hospital following the crash on the new Sheppey crossing bridge in Kent, which started at around 7.15am.

It then continued for 10 minutes as cars and lorries crashed into each other in visibility that was down to 25 yards with many people - including a family with a nine-month-old child - having narrow escapes.

It is believed to be the biggest accident in fog in living memory with around 200 people seen by medical staff at the scene on the London-bound carriageway travelling off the Isle of Sheppey.

Lives were probably saved because an unidentified quick-thinking lorry driver used his truck to block the entrance to the bridge and stop more cars piling into the crash.

Chief Inspector Andy Reeves, from Kent Police, said: "It is truly miraculous. Looking at the extent of the incident, the number of vehicles and people involved, the damage to some of those vehicles, I think we're all very fortunate there were no fatalities."

Mr Reeves said it was too early to say what had caused the accident but the heavy fog, which often shrouds the bridge, and driver behaviour are possible factors.

There were reports of some motorists driving "like idiots" in the conditions before the crash, which completely closed the A249 that goes over the seven-year-old bridge that opened in July 2006.

Police would also look at the lack of lighting on the structure - a design issue that has been highlighted by the area's Conservative MP Gordon Henderson.

Speaking at the scene, Mr Reeves said: "In conditions of thick fog, a significant number of vehicles have been involved in a number of collisions. Visibility was very bad, I understand visibility was down to 25 metres in thick fog, and clearly visibility will be a key factor in our considerations, but at this stage we haven't yet determined what caused the start of the crash."