Personal strife set Hamilton back in 2010

The fourth-placed McLaren driver said he is trying to banish "outside intrusions" from his mind in 2011.

Lewis Hamilton did not specify what issues in his personal life had affected his career.

Lewis Hamilton pointed to problems in his personal life as a contributing factor to his failure to recapture the Formula One title and said he is trying to banish "outside intrusions" from his mind in 2011.

Reflecting on a tough season that he rated as a 6 on a scale of 10, the 2008 world champion offered a glimpse into issues troubling him away from the track and said in a radio interview he hopes to "smooth everything off".

Hamilton did not specify what was bothering him, but the McLaren driver's season began in March amid the fallout from the decision to drop his father, Anthony Hamilton, as manager.

Hamilton won just three of 19 races as he finished fourth in the 2010 drivers' championship.

"The personal life, the way things have gone have not been as smooth and as happy as they could have been in the past and to do what I do is a combination of many, many things that are surrounding you," Hamilton told BBC Radio One.

"It's not just arriving at the race track and driving, it's your appearances, it's your mood swings, it's the people that are around you - your family and your friends - and the time that you are able to give to them and the relationship that you have with them.

"As soon as some of those things are off - and you've not got all those pieces of the puzzle in place - then it makes it very hard to do other aspects of your life as easily. The key, I think, to life is getting all those pieces of the puzzle in place."

Hamilton's relationship with the Pussycat Dolls singer Nicole Scherzinger does not appear to be one of his problems, with the Briton indicating that the romance - often described as on-off in the British media - is on track, referring to her as "my girl".

The driver said finishing fourth in the drivers' title race was not something of which he was proud. "It's been a long time since I finished out of the top three of a championship in my career," he said.

He said he wants to ensure he is more relaxed in 2011, saying that then "you are able to focus on your job - even better perhaps than you have in the past".

"My plan right now is to … smooth everything off and make sure that next year I am 100 per cent clear in my mind and have no outside intrusions, mentally," he said.

The new season begins on March 13 in Bahrain.