Lewis Hamilton wins 2014 F1 championship: Hamilton's career from karting champion to Formula One king

Hamilton's decision to end his 14-year association with McLaren to join Mercedes pays off as he claims his second world championship crown

Lewis Hamilton is showered with champagne after the race (EPA)

Just over two years ago, the critics lined up to question Lewis Hamilton's sanity.

His decision to end a 14-year association with McLaren and join Mercedes was met with scorn - after all, Mercedes had won just one race in three seasons following their return to Formula One in 2010 as a manufacturer.

Hamilton had been nurtured by McLaren from the age of 13 and then groomed to be a world champion, a dream he realised in 2008 after falling a single point shy the previous year

Those startling two years suggested here could be someone to perhaps emulate McLaren great and Hamilton's personal hero Ayrton Senna, whose three titles were all achieved with the team.

But by the end of 2012, Hamilton had gone four more years without another championship to his name.

He had a sniff of glory in 2010 when he went into the final race of the season as the outsider in a four-horse race and in need of a miracle which never happened.

Two years ago Mercedes' non-executive chairman Niki Lauda - like Senna a three-times champion - spoke to Hamilton and convinced him he could again become an F1 force if he jumped ship from McLaren.

If Hamilton was initially sceptical, he was soon won over. Hamilton was deemed foolish by some, who felt this was a clear sign that his occasionally suspect temperament had got the better of him.

Karting and motor racing was Hamilton's staple diet throughout his formative years, with father Anthony at one stage holding down three jobs to ensure his son could follow a path seemingly written in the stars.

Girlfriends and going out with mates were simply not on the agenda.

When McLaren confirmed at the end of 2006 that Hamilton would make the step up to F1 the following year at the age of 22, it was clear then all the sacrifice and pain had been worthwhile.

Six years with McLaren followed, during which time you could sense Hamilton was trying to find himself, to discover his true identity after many years cocooned in his motorsport bubble.

Hamilton joined McLaren in 2007 to partner Fernando Alonso (GETTY IMAGES)

Hamilton began sporting tattoos, hanging out with rappers and movie stars, and, of course, dating pop star Nicole Scherzinger.

The 'on, off, on again' nature of that relationship, combined with the bitter and public fall-out with his dad at the start of 2010 undoubtedly played on his mind at times and occasionally affected Hamilton's form on track.

The 'playboy' tendencies have disappeared, and while there might still be trappings of wealth, such as his private jet and the gold jewellery, he appears far more grounded these days.

Hamilton is now reconciled with his father and settled with Nicole, two key ingredients behind his improvement at the wheel.

Hamilton's first year with Mercedes in 2013 was one of growth and of learning, with the team having primarily moulded themselves around the needs and suggestions of seven-times champion Michael Schumacher.

With a car more suited to his tastes this season, and with Mercedes head and shoulders above rivals Ferrari and Renault mechanically, Hamilton's talent and the team's development capabilities have combined to finally help him become a Formula One world champion for a second time.

It has arguably cost him a friendship as he and Mercedes team-mate Nico Rosberg, once close as teenagers, have now suffered a parting of the ways as adults and rivals.

Hamilton, though, will not care as he can now step forward and have the last laugh on those who dared to claim he was so foolhardy in 2012.