Hamilton will drive Mercedes forwards, says Horner

Lewis Hamilton can be a driving force for Mercedes this season after their strong showing in testing, according to Red Bull principal Christian Horner.

Whether the works team can be a consistent threat over the course of the 19-race Formula One championship, after being off the pace for much of 2012 and finishing fifth overall, remains to be seen.

"Mercedes have recorded some head-turning times with the programme they have been operating to," Horner, whose own team will start as favourites for fourth successive constructors' and drivers' titles with triple champion Sebastian Vettel, told reporters on Wednesday.

"Their car looks quick, and with Lewis joining the team they will naturally take a step forward. He is worth lap time, which is why they signed him.

"I'm sure they're going to be a factor this season. Their challenge will be sustaining it over the whole season as they've been quick the last couple of years at the beginning - winning the third race in China last year."

Hamilton has joined Mercedes from McLaren, the team that backed him through his teenage years and gave him a sensational F1 debut in 2007 before his 2008 title year, in place of retired seven-times world champion Michael Schumacher.

The 28-year-old Briton and his German team mate Nico Rosberg were fastest on the final two days of testing in Barcelona last weekend with laps quicker than both the race lap record and the 2012 pole position time.