A BBC Panorama programme is to expose claims of "unethical conduct" related to the 2012 Olympic bidding process.
The IOC has set up an inquiry into the allegations
The BBC's Olympics correspondent Robert Nisbet looks at the allegations and the possible consequences on London's bid in light of the International Olympic Committee's decision to launch an inquiry.
What are the allegations?
BBC reporters posed as business consultants keen to help bring the 2012 games Olympics to London's East End. They then approached freelance sports agents who claimed to exert influence over certain IOC voters - for a fee. At least one IOC member is thought to have agreed to meet the fake businessmen - a serious breach of IOC guidelines.
What has been the response of both the IOC and London 2012?
The IOC has tried to pre-empt the Panorama programme broadcast on BBC One on Wednesday by beginning an immediate inquiry. It will be run by the IOC's Ethics Commission which was set up after the Salt Lake City scandal in which 13 Olympic officials were accused of taking bribes from organisers of the Utah city's bid to host the 2002 Winter Games. London 2012 has distanced itself from the programme. The chairman Lord Coe said his bid team has acted 'properly and ethically'.
How much of an embarrassment is this to the Olympic committee?
If the allegations are proved to be correct, it could be extremely embarrassing - especially with the start of the Athens Olympics just two weeks away. After the Salt Lake City scandal Jacques Rogge was elected as IOC president and promised to end corruption in the movement. Since then, his vice-president Kim Un-Yong has been jailed for embezzlement. Now he must deal with these fresh allegations about the IOC.
Where does this leave London's bid?
At the moment the focus is on the IOC rather than the individual bid cities. But the London 2012 team will be concerned that embarrassing revelations from the country's largest broadcaster could turn voters away from the British bid and on to the other contenders: Paris, New York, Madrid and Moscow. The London team say they had nothing to do with the allegations made in the Panorama progamme. Apart from stories about a power struggle at the London bid headquarters, Lord Coe has won praise from IOC members for his first few months in the job.
What are the IOC rules on contacts between its voters and the bid cities?
The IOC's Code of Ethics says those involved in deciding an Olympic bid and their representatives are banned from soliciting, accepting or offering "any concealed remuneration, commission, benefit or service of any nature" related to the organisation of the Olympic games.
Only gifts "of nominal value" may be given or accepted, and only as a sign of friendship. Any other gift must be passed on to the organisation the beneficiary is a member of.
It also says that the parties "shall neither give nor accept instructions to vote or intervene in a given manner within the organs of the IOC".
Finally, the cities wishing to organise the games "shall refrain... from approaching another party, or third authority, with a view to obtaining any financial or political support inconsistent with the provisions" of the Code of Ethics.