Dorset-based Olympic sailor Ben Ainslie admits his place in the squad for London 2012 is not guaranteed.
"The results that we had in the past are important but this is a fresh Olympics cycle," the 34-year-old told BBC Radio Solent.
"There's only one spot per class per nation so competition is fierce."
Earlier this year Ainslie confessed that London 2012 would be his last Olympic Games and he has spent the last two years focussing on match-racing in the America's Cup.
However, the Macclesfield-born Olympian has since returned to Finn class sailing but admits he has struggled to rediscover his form.
"It's never any easier and Finn class is a pretty physical class, I'm 34 now so physically it's been tough," he said.
"I've been away from the Finn class for two years so getting my fitness back up to where it needs to be and getting to grips with the boat again has been hard work.
"But it's been going well, I've been happy with the last couple of results I've had in the big national regattas and I'm looking forward to the up and coming event."
The British sailing team will next compete at the Sail for Gold regatta in June at the Olympic venue in Weymouth Bay and Portland Harbour.
The squad will then spend the rest of the summer competing at the Olympic Test Event between 31 July - 13 August for a place in London 2012.