London: Red Bull team boss Christian Horner insisted his veteran driver David Coulthard belies his age and is keener than ever to prove he still has what it takes to compete at the highest level. David is tremendously motivated," he said on Thursday.

"He has worked extremely hard in the past two years with the team, he has been an instrumental part of the team and he has gone about his off-season with more effort than before," he said.

"He's training harder and he is physically fitter than he has ever been," added Horner of the Scot.

 "He is motivated, anxious to get going and looking forward to seeing how the new car goes. He has big expectations for the season ahead and I have not seen him more motivated or fitter," he said.

Red Bull are expecting to see a marked improvement this year after stagnating in the latter part of 2006 especially with the first car designed for them by Adrian Newey, the technical guru who helped Williams and McLaren to multiple constructors' titles.

Coulthard worked with Newey previously at both teams and has taken all his 13 grand prix wins in cars designed by the balding boffin.

Red Bull have also traded their Ferrari engines for Renault ones and have signed experienced Australian Mark Webber from Williams as Coulthard's team-mate.