Now I'm just excited and even more determined than I have been in the past Lewis Hamilton

Briton Hamilton was pipped to the F1 title in the last race in a year that was marred by his frosty relationship with former team-mate Fernando Alonso.

As McLaren unveiled their new car for the 2008 season, Hamilton said: "Every year I grow, with the knocks, mistakes, disappointments, even race victories.

"I honestly believe I can do an even better job this season."

Report: McLaren unveil new car for 2008

The 23-year-old finished second behind Ferrari's Kimi Raikkonen in his rookie season, but a remarkable campaign was overshadowed by a well publicised breakdown in his relationship with Spaniard Alonso.

McLaren were also fined �50m and stripped of their constructors' points in the Ferrari spy row.

Alonso has since returned to Renault, with Heikki Kovalainen travelling in the opposite direction, and Hamilton insists he and the team are now in better shape than ever.

"I wouldn't say that what happened last year was a blow, but you wouldn't be human if you didn't feel anything," he said.

"But I've recovered from it and I feel even stronger, mentally and physically, and now I'm just excited and even more determined than I have been in the past.

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"Last year was a steep learning curve. I knew what I wanted last year, but it was having that desire and not really knowing how to fill the shoes 100%.

"This year, I feel more at home, more confident and more relaxed, and even more sure of what I want.

"I just believe it's a fresh start for us all, turning over a new leaf."

Hamilton and Kovalainen will test the MP4-23 in Spain later this week ahead of the new season, which starts on 16 March with the Australian Grand Prix in Melbourne.

And McLaren team boss Ron Dennis said: "Our ultimate aim is to be competitive for the drivers' and constructors' championships.

It was just the best year of my life but I know it can be better Lewis Hamilton

"Everybody worked hard at the end of 2007 so that the car would be ready as quickly as possible to allow our drivers to test it for the longest possible time."

Hamilton, who missed out on the driver's title by a single point, added: "I've done a lot of really good preparation already, way before the first test even.

"My engineer said that it needed 14,000 working hours to ensure that the car was ready for Monday. I'm really looking forward to driving it for the first time on Thursday.

"I thoroughly enjoyed last year, just the whole year. It was just the best year of my life but I know it can be better."

McLaren chief executive Martin Whitmarsh said the new car already looked promising.

"We already know that the car is quicker than the one we raced in Brazil at the end of last season," he said.

"There's a lot more lap time to be added to the car before the start of the season."

Kovalainen said he was confident he would be treated as Hamilton's equal, even though he has just joined a team that the Englishman has been with for 10 years.

"I would not have come if I did not think I had a chance to fight for the championship," insisted Kovalainen.

"We don't know how the season will develop, but I have the same opportunity as Lewis.

"So it's up to me to build a relationship with the team and make it as strong as possible, and then we will see what happens."