Attention has focused on the family firm which owned the coach that crashed on the M25, killing five, on Saturday night.

WR Spring & Son, based in Evesham in Worcestershire, was founded 54 years ago by Roy Spring, now 83.

It runs coach tours around the UK and has been running cross-channel trips without accident for 30 years, said Mr Spring's daughter Pam.

The crash happened as 41 passengers from the local area were returning from a day trip to French hypermarkets.

My brother, who was killed in the crash, did all the maintenance and he was very, very strict

Pam Spring WR Spring & Son

The driver, Roy's 56-year-old son Graham Spring, was killed, as was his co-driver, Christopher Sloane, who was in his late 30s.

Mr Spring had been the "rock of the business" since their father suffered a stroke earlier this year, said his sister.

She said the company had "absolutely no idea" what could have caused the crash.

The coach had begun its trip at 0500 GMT on Saturday morning, but there was no reason to suggest either of the drivers was tired, she said.

"My brother's done this trip many times before. He's a very experienced driver, he's been driving since he was 21.

"Christopher Sloane also has been with us for 10 years, and is an experienced driver on the continent and in this country.

"He was very loyal to the company and he was a lovely man," she said.

Police have been unable to confirm which one of the pair had been driving the coach when the crash occurred.

But one passenger said the two men had swapped over shortly after landing back in England following the Channel crossing.

'Brand new' parts

Ms Spring said the coach was nine years old.

Its maintenance regime was "rigorous" and regular, and the vehicle would have been checked before the trip.

"My brother, who was killed in the crash, did all the maintenance and he was very, very strict," she said.

"Nothing was put on those coaches unless it was brand new - tyres, parts, everything.

"They were regularly checked and brought in, they were checked every week.

"And before they went on a trip like this they were put over the pit and they were checked again."