Former Foreign Secretary Malcolm Rifkind has accused the US of delaying the verdict in Saddam Hussein's trial to coincide with the mid-term polls.
Mr Rifkind said the timing was "deeply suspect"
He told BBC One's Question Time he had no evidence but the timing of the verdict was "deeply suspect".
The former president of Iraq was this week sentenced to death by hanging for crimes against humanity.
The White House has dismissed similar accusations as "preposterous" and said the Iraqi judges determined the timing.
It comes as Egyptian President Hosni Mubarak warned that hanging the former dictator could lead to further bloodshed in Iraq.
Making the first public comments by an Arab leader on the sentence, Mr Mubarak said such a move would only enhance the country's sectarian and ethnic divisions.
Tory MP Sir Malcolm said he believed the US told the Iraqi court to hold off until just before the US elections.
Saddam Hussein was sentenced on Sunday but despite that President Bush's Republican party lost control of both the House of Representatives and the Senate in Tuesday's mid-terms.
Many of the losses were put down to anger over the Iraq war. One of its key architects, US Defence Secretary Donald Rumsfeld, has since stood down.
Saddam Hussein's death penalty has been condemned by human rights groups and the European Union has urged Iraq not to carry out the sentence.
But President Bush welcomed the verdict as a "milestone" in the efforts of the Iraqi people "to replace the rule of a tyrant with the rule of law".
A Downing Street spokeswoman said on Thursday the "Iraqi judicial system is a matter for the Iraqis" and refused to comment on Sir Malcolm's "suspicions".