Four-time Olympic sailing champion Ben Ainslie has admitted that it was a "tough decision" to call time on his Olympic career.

The 35-year-old has retired as an Olympian after earning four golds and a silver to become the most successful sailor in Olympic history, and he has revealed that he will now pursue his dream of winning the Americas Cup.

Ainslie told BBC Sport: "It was a tough decision. I've had a fantastic Olympic career but I want to make it clear that the focus is now on the Americas Cup.

"I considered all of the factors - my fitness and the issues with my back, the venue for the next Olympics and the type of boats, but what it really came down to was this opportunity with the Americas Cup.

"It's always been a dream of mine since I was a kid to be part of a winning Americas Cup team and ultimately I want to try and bring it back to the UK where it all started in 1851."

Ainslie has been placed on the shortlist for this year's BBC Sports Personality of the Year award.