A Tory former minister has warned he is prepared to vote against the Government unless Prime Minister Theresa May gives Parliament a proper say on any Brexit deal.
As the Lords threatens to impose an amendment on the Brexit Bill specifying Westminster must have a "meaningful" vote on a withdrawal agreement, Bob Neill signalled he could support such a move if it came back to the Commons.
Asked on BBC Radio Four's Westminster Hour if he would back such an amendment, he said: "I'd certainly be inclined to vote in that way unless the Government is able to come up with alternative assurances on the floor of the Commons which has the effect of saying, 'it needn't be on the face of the Bill but this is what will happen'."
Pressed on whether he would trust assurances that were not included in the legislation, Mr Neill said: "That would depend precisely on the form of words that was used, and that's why the ball is in the Government's court.
"I want something that specifies not only the timing of the vote, which I think we have got now - before it goes to the European side and the European Parliament for ratification - but I also want it made clear that there is a vote on whether or not there is a deal or no deal.
"If there is no deal, that means that we would potentially leave the EU straight on to World Trade Organisation terms and without any transitional arrangements. I believe that would be deeply damaging for this country and I think Parliament should have the right to consider that."
Commons Leader David Lidington cautioned the Lords against amending the Brexit Bill to include a clause for a "meaningful vote" in Parliament at the end of the negotiating process.
He told the BBC: "Parliament will get the chance to vote on the deal.
"Any idea that the PM's freedom to negotiate is limited, any idea that if the EU 27 were to play hardball, that somehow that means that Parliament would ... try to reverse the referendum verdicts, and to set aside the views of the British people - that would almost guarantee that it would be much more difficult to get the sort of ambitious, mutually beneficial deal for us and for the EU 27 that we want."
The comments came after Chancellor Philip Hammond warned the EU that the UK would "fight back" and not "slink off" like a wounded animal if it did not get the Brexit deal it wanted.