Fernando Alonso: Ferrari F1 team doubts began in 2013

The Italian squad finally confirmed on Thursday that two-time F1 champion Alonso was leaving at the end of the season, after five years together, to make way for Sebastian Vettel.

Although Alonso revealed he had informed Ferrari of his decision to leave in September, the Spaniard conceded plans for a possible exit had already began to take shape during the latter part of 2013.

"It was not a special moment of the year that I opened my eyes," said Alonso in Abu Dhabi. "Last year I had some doubts about 2014.

"I knew that it was a big change of regulations so I thought best thing to check how the 2014 new turbo era was going for Ferrari.

"I had a very close relationship with president [Luca] di Montezemolo. We talked every week and we more or less agreed that if this year we were not competitive again we could think of different options.

"In the summer break it was time to sit with the president and say, 'OK, I would like to go'."

This year Alonso has endured his worst season since joining Ferrari and is set to finish without a victory for the first time since 2009.

Alonso is expected to move to McLaren, but the British team said it will not announce any plans until next month.

"Obviously it is a new chapter in my career, and I think I felt it was the time to find new projects, new motivation, and it was not an easy decision to make," Alonso said.

"I was in talks even last year, to be honest, and we waited for this year, the new car, the new turbo era, and this year I felt around summertime/September that it was time to move, and I made the decision.

"Only time will tell if it is a good one or bad one."

He said Ferrari would always be close to his heart.

"I am so happy, so proud to have those five years with this amazing team. I grew up as a driver and a person," Alonso added.

"We missed the championship, came three times second but I'm extremely proud of those second places and the work we did those years.

"Now it is time to close one door and open a new one and we see how it goes.

"I stop as a Ferrari driver but from Monday I am a Ferrari supporter."