FIFA in crisis: 'Morocco won 2010 World Cup vote - not South Africa'
New corruption allegations against Fifa claim Morocco won the 2010 World Cup vote instead of South Africa, who ended up hosting the contest.
Claims have emerged that Fifa and Sepp Blatter were allegedly handed tapes of one official, Ismail Bhamjee, revealing Morocco had won five years ago.
It is also alleged Morocco and South Africa bribed officials - allegations they deny.
The taped conversations were made as part of an undercover investigation into Fifa by the Sunday Times five years ago, it claims it handed its evidence to Fifa to investigate at the time.
It comes as Fifa president Sepp Blatter resigned on Tuesday saying he would remain in charge until a special congress can choose a new leader and vowed to pursue strong reforms in that time.
Blatter noted that he had just won re-election from Fifa members, but said: "I do not feel that I have a mandate from the entire world of football."
Russia and Qatar's status as hosts of the 2018 and 2022 World Cup tournaments has been thrown into doubt following the announcement.
Sources close to the case said that Mr Blatter is being investigated by the FBI and US prosecutors as part of the same investigation that led to the arrests of seven current and former Fifa officials.
Commenting on his resignation, Greg Dyke, the chairman of the Football Association, had said: "Clearly there's a smoking gun. It's not to do with Sepp Blatter being honourable."
Mr Blatter had been re-elected as president of Fifa for another four-year term, having resisted calls from some of the sport's most respected voices to quit.
England, one of the countries that bid unsuccessfully for the 2018 World Cup, will now be alert to the possibility that it could yet win the right to stage the tournament if Fifa's 2010 voting process is declared null and void by Mr Blatter's eventual successor.