LONDON (Reuters) - Twice world 400 meters hurdles champion Kerron Clement has not enjoyed his first morning in London after the bus transporting him from Heathrow Airport to the Olympic village was lost for four hours en route.

"Um, so we've been lost on the road for 4hrs. Not a good first impression London," American Clement said on the social network site Twitter.

"Athletes are sleepy, hungry and need to pee. Could we get to the Olympic Village please?"

Athletes and officials have started arriving at the Olympic village ahead of the Games that open in 11 days' time.

Long tailbacks have been reported on the M4 motorway coming into London after the first priority 'Games Lane' went into operation on Monday while Heathrow is expecting its busiest day on record.

Clement, 26, won the world title in 2007 and 2009 before losing out to Britain's Dai Greene in Daegu last year.

(Reporting by Toby Davis; editing by xx)