Butt claimed he heard from bookmakers that England were paid to lose FridayÃ¢â‚¬â„¢s one day international at the Oval.
The Pakistani chairman told IndiaÃ¢â‚¬â„¢s NDTV television channel: Ã¢â‚¬Å“There is loud and clear talk in bookie circles that some English players were paid massive amounts of money to lose.Ã¢â‚¬Â
In a letter, the ECB warned that legal proceedings would commence should no such apology be received.
This news comes on the back of former England captain Michael VaughanÃ¢â‚¬â„¢s plea for England to take legal action.
Ã¢â‚¬Å“IÃ¢â‚¬â„¢d be making a few phone calls to legal sources to try and take this a little bit further,Ã¢â‚¬Â said Vaughan. Ã¢â‚¬Å“I canÃ¢â‚¬â„¢t think of anything worse than your name mentioned in terms of fixing a game of cricket.Ã¢â‚¬Â
An apology from Butt is expected after he told BBC Radio Five Live he has no proof and was simply stating what he had heard.
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BIOGRAPHY: Cesc Fabregas