The England team have demanded a "full and unreserved apology" from Pakistan Cricket Board chairman Ijaz Butt, who alleged they were involved in fixing matches.
They are also threatening legal action after the claims relating to the third one-day international at the Brit Oval.
The controversy arose when Butt said on television in Pakistan: "There is loud and clear talk in bookie circles that some English players have taken enormous amounts of money to lose the match [the third ODI]. No wonder there was such a collapse."
The fourth and fifth matches of the series did go ahead as planned despite talk that England would pull out.
But the England and Wales Cricket Board (ECB) and the Professional Cricketers Association (PCA) released a statement which read: "The ECB and the PCA (today) confirmed that a pre-action letter has been sent on behalf of the England cricket team to Ijaz Butt, Chairman of the Pakistan Cricket Board, following his allegations that the England cricket team were involved in fixing the outcome of the third NatWest Series One Day International between England and Pakistan, played at The Brit Insurance Oval on September 17th 2010.
"The letter seeks a full and unreserved apology.
"Mr Butt has been advised that if a satisfactory response is not received, legal proceedings will be commenced against him without further notice."