GOOD Samaritan Megan Grange comforted a driver trapped in the wreckage of his car after a multi-vehicle smash outside her home.

She talked to the driver, a 38-year-old man from Calne, and kept him covered with a blanket until firefighters arrived at the scene of the head-on collision involving a milk tanker, which happened on Friday, halfway up Black Dog Hill on the outskirts of Calne.

The man's legs were trapped under the crumpled dashboard of his Astra car and it took fire crews 40 minutes to cut him free.

Mrs Grange, 36, then made cups of tea for the firefighters as they turned their attention to the stricken tanker, which had spun across both lanes of the A4 before hitting a tree and overturning on its side.

Environment officers feared the tanker's cargo of 900 litres of milk could harm river life if it was allowed to escape into a tributary of the Marden 250 yards away.

Mrs Grange, who works in the Lansdowne Arms, in Derry Hill, and lives opposite to where the crash took place, said: "I'd just pulled into the driveway after work. I didn't hear the crash, but I heard screaming. I went to see the man in the Astra, who was clearly trapped, but he was still conscious. I talked to him and then went to see if the driver of the tanker was ok.

"He was just getting out of his cab so I knew he was all right. I then went back to the man in the Astra, got him a blanket and waited with him until the emergency services arrived.

"He was really calm. All he could say was can you telephone my childminder, but his phone was trapped under the dashboard."

Mrs Grange's husband Wayne, 40, said: "I was upstairs and all I heard was this massive crunch and that's when I saw the carnage. Then I telephoned the emergency services."

Sgt Craig Hardy from the central traffic group at Westbury said police suspect the 3.10pm accident occurred after a yellow car travelling down the hill stopped suddenly.

He said a Rover and a Clio behind the yellow car collided and it appeared the white Astra may have been unable to stop and attempted an overtaking manoeuvre. But as it went round the two cars, it collided with the tanker travelling up the hill.

Leading Firefighter Tom Burns from Calne said: "When we got to the scene we noticed someone talking to the man trapped in the car and reassuring him.

"It's good to have the support of the public, certainly in terms of assisting the injured until we arrive. Items such as the blanket the lady brought out can make all the difference to a casualty until the emergency services arrive."

Sgt Hardy said the driver of the Astra was taken to the Great Western Hospital, in Swindon, by air ambulance suffering from a suspected fractured leg and pelvis. He said the other drivers were treated for minor injuries.

North Wiltshire District Council transported five tonnes of sand to the scene, which firefighters used to build a half-a-metre high barrier to absorb the milk if it escaped.

A water-filled plastic boom was positioned across the A4 20 metres beyond the sand wall and firefighters blocked drains on the edge of the road, which led to the nearby waterway.

A spokesman for the Environment Agency said: "As milk biodegrades very quickly it requires oxygen. If it gets into the river this starves other creatures of oxygen and it can be quite a threat to river life."

Three recovery vehicles, including a crane, were used during the two hour operation to right the tanker after milk was pumped into an empty tanker behind the wreck.

The A4 was closed between Calne and the Pewsham junction at the bottom of the hill for five hours. Police are appealing for witnesses and in particular the driver of the yellow vehicle to ring them on (01249) 654455.