AUSTRALIAN GRAND PRIX Venue:
Albert Park, Melbourne
Comprehensive live coverage of Friday's practice sessions, Saturday's qualifying sessions and Sunday's race across BBC TV, radio and online.
Find complete listings here
Hamilton backtracked on comments saying he may leave McLaren
Lewis Hamilton begins the defence of his Formula 1 title at the Australian Grand Prix this weekend - but admits he may struggle to keep up in Melbourne.
After a winter of radical rule changes and financial uncertainty, this season promises to be keenly contested.
McLaren have struggled during testing and Hamilton admits they face an uphill task to keep up with their rivals.
"We'll have pretty much the same people challenging for the title as last year - except for us obviously," he said.
Hamilton will be involved in first practice at 0125 GMT on Friday, with qualifying on Saturday at 0500 GMT and Sunday's race begins at 0700 BST.
His downbeat assessment comes after a miserable winter for McLaren - team principal Martin Whitmarsh said two weeks ago the team "had not done a good enough job".
Whitmarsh added: "We have an underdeveloped car, we do not have sufficient aerodynamic downforce and we would like to focus on rectifying that as quickly as we can."
And Hamilton is quick to play down his chances of retaining his crown.
All I said was that it's quite cool if you find out other teams are interested in you - it's good to know you are wanted
"World champion is a great title to have next to your name," said the 24-year-old Englishman. "But I have reset the targets.
"I do want to be a world champion again - but it will be tough this year."
The mood at McLaren was not helped on Thursday when Hamilton apparently hinted that he could talk to other teams if McLaren continued to struggle.
"I haven't had any offers from other teams, and I am not talking to anyone." he said. "But I would listen to an offer if someone asked. It would be a compliment and it would be silly if I did not."
Hamilton later played down these comments, insisting he is "happy" at McLaren.
"All I said was that it's quite cool if you find out other teams are interested in you," he added. "It's good to know you are wanted."
While McLaren have struggled, some unexpected names are expected to run at the front this year.
The newly-formed Brawn GP team have set the pace in pre-season testing and many local bookmakers have made their English driver Jenson Button the race favourite in Melbourne.
Exclusive interview: Hamilton chats to BBC Sport about being defending champion
The Northamptonshire-based outfit arose from the ashes of former team Honda, who withdrew from the sport in December last year as a result of the global financial crisis.
Brawn's form has surprised many, especially as the team only announced it would run this season at the beginning of March.
Constructors' champions Ferrari have also looked good over the winter, as have BMW, Toyota and Renault.
BMW's Polish driver Robert Kubica has been touted as a possible title contender, while Renault's double champion Fernando Alonso has said he also expects to be in the mix.
But the start of the new season has been soured by a row over a part used by Brawn GP, Williams and Toyota.
Rival teams have argued that the design of their rear diffuser - the part of the floor of the car below the rear wing and between the rear wheels - gives them a substantial aerodynamic advantage and have lodged a protest.
The protesting teams claim the controversial diffusers create more downforce and give a lap-time benefit of as much as 0.5 seconds.
Success this season will depend largely on which teams have adapted best to a raft of rule changes which are intended to promote overtaking and lead to more exciting races.
This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.