Shadow Brexit secretary Sir Keir Starmer (Image: Luke MacGregor/Bloomberg via Getty Images)
The Labour MP said that Parliament will have to intervene with a "hard stop" over concerns Mrs May will attempt to leave MPs with a choice of accepting her deal or crashing out of the European Union without any agreement. Speaking in Dublin ahead of a series of meetings with unions, business and political leaders, Sir Keir again called on Mrs May to have a vote on the customs union. Referring to her letter to Labour leader Jeremy Corbyn, Sir Keir said the key question is whether Mrs May is prepared to move her red lines on the Brexit deal.
In her response in the letter, the Prime Minister said she wanted the Tory and Labour teams to consider "alternative arrangements" to the Irish backstop.
"The point of the exercise is to say there is a majority for a close economic relationship if you are prepared to try to find it and I said we should test that by having a vote on the customs union," Sir Keir said.
"The Labour Party has some concerns about the backstop but we absolutely accept that it's inevitable that we need a backstop. At this stage of the exercise, the Article 50 window is almost being closed now so we need a backstop.
"The letter was an agreed letter that was sent out. The critical question is, is she, in her response, indicating a willingness to drop her red lines or not and that's what needs to be tested sooner rather than later.
Sir Keir said the key question is whether Mrs May is prepared to move her red lines on the deal (Image: Getty Images)
"I am concerned that with 46 days to go the Prime Minister is simply running down the clock, mindful that the next EU Summit is March 21 and if she's is trying to run the clock down Parliament has to step in with a hard stop to say we are not going to acc
"The critical thing is which direction is the Prime Minister heading in. Is she firstly trying to get her own team back on board to put her deal yet again with some supposed changes, and that's what looks like she is doing, or is she genuinely