As the EU (Notification of Withdrawal) Bill returned to the Commons from the Lords, I was able to intervene in the Minister’s statement:

The Minister is asking us to take him at his word—on trust. Given the record of the Conservative party recently on manifesto commitments, does the same principle of trust apply?

Mr Davis:  I said before, and I will say it again: I take statements at this Dispatch Box as binding.​

The important point here is that the idea that Parliament could force the Government to accept a bad deal will only incentivise those on the other side of the negotiating table to deliver just such a deal. As the Lords European Union Select Committee—hardly a Tory front organisation —said:

“The Government will conduct the negotiations on behalf of the United Kingdom, and, like any negotiator, it will need room to manoeuvre if it is to secure a good outcome.”