A father has paid tribute to his “marvellous” son who died at a classic motorbike race after being poisoned by toxic fumes from a smouldering barbecue.

David Swallow, 29, a former pupil of Yorkshire Martyrs Catholic College, Westgate Hill Street, Bradford, fell asleep in the back of a van by the barbecue following a day’s racing with his dad Bill at the East Fortune circuit in Scotland.

They had moved the barbecue into the van where David was to sleep as it started to go out.

When he went to wake David the next morning, Bill Swallow, 59, discovered his son having a seizure in the back of the van.

He fell into a coma and died of suspected carbon monoxide poisoning five days later at Edinburgh Royal Infirmary.

Paying tribute to David, Mr Swallow, who is known nationally as a classic motorcycle racer, said: “He was a marvellous son. I can’t believe the quality and the number of tributes from people who knew him.

“He made a big impression on people. He rode bikes for a couple of people and they treated him like the son they never had.”

Father and son had been at the Bob McIntyre Memorial Classic Races 2010, at East Fortune Aerodrome Raceway, East Lothian, on the Saturday night, when tragedy struck.

After finishing the barbecue, they put it in the back of the Renault van – believing it had gone out – and went for a walk.

When they returned about two hours later, David went to sleep in the van.

Mr Swallow called an ambulance after finding him at about 8.30am the next day.

“We got him to Edinburgh Royal Infirmary and they got an oxygen mask on him,” said Mr Swallow. “He was there for five days and never came out of his coma.

“It was only on the way to the hospital that I thought it could have been the barbecue.”

A post-mortem examination revealed David had much higher levels of carbon monoxide in his blood than was expected. A spokesman for the Edinburgh Procurator Fiscal’s office, which investigates sudden deaths, confirmed it had received details of Mr Swallow’s death, which occurred on June 24.

Durham University graduate David, a keen fell runner and footballer, also leaves his wife Ruth and brother Chris.

His funeral will take place at Huddersfield Crematorium on Friday at 11.30am.

Mourners are requested to wear informal dress.

e-mail: marc.meneaud@telegraphandargus.co.uk