The dad of top motorcycle racer David Jefferies today spoke of his "terrible sadness" at his son's death.

Thirty-year-old David was killed instantly in a horrific accident in a practice session at the Isle of Man TT Races yesterday.

A full-scale inquiry has been launched into the incident, which happened at Crosby. David's powerful 1000cc Temple Auto Salvage GSXR Suzuki is believed to have hit a telegraph pole. Two other riders are also understood to have been injured.

Mr Jefferies, who lived at the family home in Baildon, was the outright lap record holder at the TT and had ridden at an average 125mph on his first lap yesterday.

He was on his second lap of the 37 mile course when the tragedy happened.

His mum Pauline, who travels with him and acts at a timekeeper at the TT races, was six miles away at the race Grandstand at the time.

Dad Tony, himself a former racer whose career was cut short when he broke his back in a racing accident in 1973 and was confined to a wheelchair, was at a BMW conference, in London, when his wife rang him to break the terrible news.

Today, he said his son never quite realised just how good a racer he was and that he had been overwhelmed by the messages of sympathy and comfort he had received in the hours since his son's death.

"The phones have never stopped. I can't even remember everyone who has rung but it's been a comfort to us.

"We are really close family and he was a really popular lad. It's terribly sad.

"I don't think David ever realised just how good he was. He was talked about in the same breath as the world greats, which was wonderful but he could not really understand that."

Mr Jefferies managed to get to the Isle of Man within two hours of his son's death, which he said he been an enormous help.

"I had been due to fly out to the Isle of Man last night. Pauline rang me when I was on a break at the conference to tell me what had happened. I managed to get a flight straight out from London with my daughter Louise," said Mr Jefferies.

" Pauline had seen him go past at 125mph on the first lap. David thought there might have been some problems with his bike and said he would come back in after the first lap if that was the case but he didn't, he carried on.

"We don't know the full story yet. David wasn't a risk taker. He rode within his limits. For this to happen, there had to be something out of the ordinary. It would appear there was something on the circuit that made this happen, although we don't know that for definite and we'll have to wait for the inquest to hear the full details."

Mr Jefferies said his son's body would not be released until an inquest had been held, probably during next week. He would then be flown home and his funeral will be held in Bradford.

The accident shocked residents on the Isle of Man, many of whom had come to know David. Tributes have also poured in from across the motorcycle world.

Philip Neil, team manager at Jefferies' TAS Suzuki team, said he was "shocked and devastated" by his death.

"Not only had David become a very close personal friend of the whole team, but he was a fantastic motorcycle rider and a real ambassador for our sport," he said.

Staff at the headquarters of the 100-year-old family firm, Allan Jefferies motorbike dealers in Otley Road, Shipley, were informed of his death yesterday by a call from David's team. No-one there was willing to comment, although they said it was a tragedy to lose a "really good friend".

Barry Robinson, who has covered motor sport for the Telelgraph & Argus since 1969 and has known the family closely, said it had been a natural progression for David to follow his grandfather, Allan, father and uncle, Nick, into the sport.

"Tony was a brilliant racer until he broke his back. His uncle, Nick, was a brilliant all-rounder.

"David had won everything worth winning but he was not a superstar, he was one of the lads. He was larger than life."

TT racing was a "family operation", he said, with David earning "hero" status on the Isle of Man.

Sue Smith, general secretary of the Yorkshire Centre of the Autocycle Union, said: "This is a very, very great loss to the sport. He was at the peak of his career. I knew him when he was trialing as a schoolboy. He was a super young man."

Shipley MP Chris Leslie said: "This is a huge loss to the sport and people's thoughts are with his friends and family."

Colin Appleyard, managing director of Colin Appleyard car dealership in Bradford, said he was a very close friend of the family and had known Dave since he was born.

"I remember him riding his first trial bike when he was just nine years old and from then on all he wanted to do was be a motorbike racer," he said.

"He was very laid back but totally dedicated to the job.

"I was due to go out there on Monday but now I'm not sure."

He said Dave, who was known as DJ or Big Dave, would call him Uncle Colin when he was younger.

"The Isle of Man was his Everest and he realised the dangers," he said.

Mr Appleyard's son Robin, who was also a motorbike racer, was also a good friend of Dave's.

Stuart Feeny, a director of Colin Appleyard's, said had known David since he was a baby and used to work at Allan Jefferies.

"He was a super lad and an absolute gentleman."

John Dickinson, editor of Trials and Motocross News, which has a worldwide circulation, also spoke of his shock.

"There is a deep cloud over the Isle of Man. He was one of the lads. He was a big lad and had a very big heart and this is a really big loss."

Jefferies' ambition was to be a professional motorcycle rider in a factory world superbike team. His achievements included nine TT wins in three years and being first winner of the Joey Dunlop Trophy.

Following yesterday's accident the red flag was displayed at the grandstand and all riders finishing their first laps were brought back into the paddock. Those who had already embarked on the second lap were stopped at Glen Vine. Today, racers were resuming solo practice sessions on the TT circuit.

Before the week-long TT practice began on Sunday, David, the race favourite, said he was hoping to break the 200mph barrier on parts of the public roads circuit.

His grandfather, Allan Jefferies, was one of the best known motorcyclists in the country and captain of the British team. He won gold medals in the international six-day trials every year from 1928 to 1948.

Tony Jefferies had his sights set on the World Championship at the time of his accident in 1973.