Coulthard fails to complete a lap in GP

SILVERSTONE (Reuters) - Red Bull's David Coulthard retired from his last British Grand Prix on Sunday after skidding off without completing a lap.

The 37-year-old, who announced on Thursday his retirement from Formula One at the end of the season, tangled with Sebastian Vettel's Toro Rosso at Priory and spun off into the gravel trap.

The disappointed Scot shouldered the blame for the accident on a rainy afternoon at Silverstone.

"I'm extremely disappointed and sorry for the team," said Coulthard.

"I've taken out two Red Bull cars so that's obviously the worst case scenario... you have to take your opportunities when they come in a race like this and I thought I saw a gap," he told BBC radio.

"Unfortunately it turned out it was a bad decision."

Coulthard started the afternoon as the last British driver to have won at Silverstone, with victories for McLaren in 1999 and 2000.

In another blow for Coulthard's team, Australian Mark Webber went from the front row of the starting grid to 18th place after spinning on the opening lap.

(Reporting by Alan Baldwin)