London's 2012 Olympic bid team has taken on a legal expert to make sure it does not fall foul of the strict rules on competing for the Games.
Leading barrister Michael Beloff QC, who is also president of Oxford's Trinity College, will act as ethics commissioner for the bid.
The International Olympic Committee imposed rigid guidelines in the wake of the Salt Lake City scandal.
And bidding cities can be ruled out of the process if they break the rules.
London 2012 Chairman Barbara Cassani said: "Mr Beloff is an internationally respected lawyer, who has held a number of significant judicial, tribunal and arbitral posts.
"I am therefore delighted that he has agreed to fill this important role and to chair our advisory group.
"This is a key element in our approach to good corporate governance and will help us maintain and ensure integrity and transparency throughout the bid process."
London's bid was recently at the centre of controversy when Prime Minister Tony Blair was accused of making an Olympic pitch at a summit of Commonwealth leaders.
Paris risked the anger of the IOC when mayor Bertrand Delanoe made a thinly-veiled criticism of London's bid, and New York and Moscow have also been warned.
Madrid, Rio de Janeiro, Leipzig, Istanbul and Havana complete the list of nine cities vying to host the Games in 2012.