Ann Widdecombe has said she is sceptical that Brexit will be delivered by October 31, insisting she "wouldn't put money" on it.
The Brexit Party MEP accused remain-backing MPs of trying to overturn the referendum outcome, and that there was only a "ludicrous proposal of a deal" on the table at present.
"Right at the beginning I was all for a deal... that to me was just common sense, but as we've gone along, the EU has been evermore intransigent, and the remainers in Parliament have been ever-cleverer about trying to undermine what is being done," she told talkRADIO's Julia Hartley-Brewer.
"What we should be very clear about is that if you get the May deal warmed up in any form - even if it was completely minus the backstop which is most unlikely - it would still be Brexit in name only."
The Brexit Party have offered to team up with the Conservative Party in order to give them a majority in any upcoming election, but this has been rejected by Boris Johnson.
But Ms Widdecombe said the Prime Minister "hasn't got a chance" without an electoral pact.
"We have already said we will not stand against those MPs who stood very fast on leaving with no deal if necessary," she added.
"We made a very good offer to Boris, which was he needs to reduce the Labour majority. Labour voters are not going to vote Tory... but they will vote for the Brexit Party, and there we've said look, we will go into those seats if you do not stand against us, and in return we will not stand against an agreed number of yours."
The MEP continued: "Together we can succeed, but on his own it's going to be Brexit to the right of him, Brexit to the left of him and remain in front of him, volleying and thundering, and he hasn't got a chance."