Usain Bolt's chances of breaking the 100 metres world record at the London 2012 Olympics could be scuppered by the British weather, according to the Jamaican's coach.
Glen Mills, head coach of the Racers Track Club of which both Bolt and world 100m champion Yohan Blake are members, believes Bolt is capable of running below 9.50 seconds.
The 25-year-old, whose world record stands at 9.58secs, has declared his intention to "amaze" the world this summer, but Mills feels the conditions may not be conducive to a 9.4s performance.
"I don't believe it's impossible, but he would have to have the right conditions," the 62-year-old said. "I'm not sure if London is going to be kind. I am talking about the weather."
The triple Olympic champion, who has been hampered by fitness problems since his world record run in Berlin in 2009, will race his first 100m of the season at the Jamaica International Invitational in Kingston a week on Saturday. Blake currently leads the world rankings with 9.90.
"Usain is in good condition, he's trained well," Mills said. "He had a first run in an invitational meeting a week ago where he anchored the Racers team to a world leading 37.82 and he is ready to run.
"I expect him to do well. He's in good shape so I'm expecting him to run a good race."
Bolt has frequently stated his desire to become a living legend in athletics by defending his Olympic crowns.
He suffered the first major setback of his career at last summer's World Championships in Daegu when he was disqualified for false starting in the 100m final, leaving Blake to take the gold medal.
But Mills feels that experience has made him stronger.
"The lesson he has learned from Daegu is you can never be too complacent, or take anything for granted," the coach said.
"You have to focus and concentrate on the task at hand. I think he's quite aware of that going into the Olympics and will certainly be in a better position not to be a victim of a false start.
"Usain is quite aware of what it takes to try to be a champion and what is needed for him to maintain the high level of performance.
"It's not difficult to get him to focus on his preparation and to do the kind of training that is required for him to do well. He has set his sights on reaching greater heights. He wants to become a legend in the sport and he's quite aware that is work is not done yet."
Mills ruled out the possibility of Bolt competing in the 4x400m relay in London, saying it was something the pair had considered but the programme made it unfeasible.
Blake, though, who will run over 200m at the Jamaica International Invitational, intends to run over both the 100m and 200m in London.
And Mills predicted he would lower his 100m personal best from 9.82 this season.
"I would love to see him go much faster than he did last year," Mills said. "His best is 9.82, we're hoping he will surpass that this year. He's training with the double in mind."