Sir Malcom Rifkind has questioned the purpose of a post-Brexit election, calling it a "totally ridiculous" idea.
His comments come amid reports that Boris Johnson is preparing for an election after October 31, in the event he loses a no-confidence vote when Parliament returns after the summer recess.
"If you are going to have a general election to resolve this issue of no deal, it would be ludicrous and totally ridiculous to have the date of the general election deliberately put after we have already left the EU," Sir Malcolm told talkRADIO's Julia Hartley-Brewer.
"That is the suggestion that was being put forward by Mr [Dominic] Cummings, who is an unelected staffer with Boris Johnson."
During his campaign to become Prime Minister, Mr Johnson said he would not call an election if he was crowned Britain's next leader.
But opposition leader Jeremy Corbyn has insisted he is willing to trigger an election when he knows his party "can win it".
The Labour leader said it would happen at an “appropriate, very early time” but gave no specific detail as to when this might be.
But according to one Whitehall official, there is "no mechanism to stop" a Halloween Brexit, even if a motion of no confidence is tabled in September.
With the government having a working majority of just one, there have been suggestions that remain parties will form an alliance in an effort to oust the Conservatives in the event of an election.
SNP leader Nicola Sturgeon has said she would be open to a pact with the Labour Party if they could form a majority and "lock the Tories out of government”.