SIX people were injured – including three children under ten – in a four car Boxing Day smash.

Seven-year-old twins had to be airlifted to hospital with serious injuries after the collision on the A174, close to Yearby, near Redcar, just before 10.15am.

Their older brother, thought to be about nine, was also rushed to hospital by ambulance with less serious injuries.

The three children were travelling in the car with their father when a Porsche is understood to have collided with their vehicle.

The seven-year-old boy, who paramedics said was wearing a Spiderman costume, was airlifted to James Cook University Hospital by the Great North Air Ambulance with head and leg injuries.

It is believed he underwent emergency surgery yesterday (Wednesday, December 26) – although the hospital could not confirm this – and was last night said to be in a stable condition.

His twin sister was flown to the same hospital with head, pelvic and abdominal injuries in the police helicopter.

Their older brother was taken to hospital by ambulance.

Reports on social networking sites suggested the family were on their way home after doing the Boxing Day dip at Saltburn.

A 16-year-old and two adults, including a 40-year-old man with chest and pelvic pains, were also treated for their injuries.

The couple in the Porsche were understood to have been treated for shock.

Cleveland Fire Brigade, which said there were six casualties, said one of the cars involved ended up on its roof and is believed to have clipped another car as it crashed.

Paul Colling, watch manager at Redcar Fire Station, said two off-duty fire officers from London and West Yorkshire happened to be passing the scene at the time of the crash and stopped to give first aid, assess the scene and call the relevant emergency services.

He said: “It was a serious incident and obviously distressing, particularly at this time of year. We had enough resources there and police, fire and ambulance worked well together to clear room to get the Air Ambulance safely down, then deal with the road closures.”

Three ambulances and five fire crews attended the incident. The A174 was closed in both directions and only reopened at about 4pm after the scene had been cleared and an accident investigation carried out.

BBC Breakfast business reporter, Steph McGovern, witnessed the accident, and tweeted: "Horrific crash on the road to Redcar A174 - at Kirkleatham roundabout - car in front of me just flipped upside down on the road.

"This is awful. Helicopter has just landed on the road. Looks like about a dozen cars involved. Emergency services all here."

Cyclist Peter Southeran passed the accident at about 10.30 and said there was a car on the central reservation and another on its roof.

Any witnesses should call the Cleveland and Durham Specialist Operations Unit on 101, quoting reference number 230130.