Theresa May's deal with the DUP has been delayed as the government deals with the Grenfell Tower blaze. Even without the tragic events of last night, there's reason to suggest that May's deal with the DUP would not have been signed this week.

Although the two parties are said to be finalising the 'terms and conditions' of an agreement, behind the scenes the DUP are driving a hard bargain as they attempt to squeeze more and more out of a beleaguered Prime Minister.

There is growing anger among Tory MPs that May has misplayed her hand in these negotiations. By announcing that the Conservatives would govern in conjunction with the DUP, she made it so that any failure to do so would look like weakness. MPs believe that entering into a formal agreement with the DUP is not in the party's interest as (a) given the DUP's record on LGBT rights, it risks toxifying the Tory brand by association, and (b) it means the power is with the DUP. They reckon May ought to have called their bluff. After all, the alternative for the unionists to voting with the Conservatives is a Corbyn-led government and given the low regard Foster's party hold the Labour leader in, they're unlikely to do that anytime soon.

For their part, the DUP are making the most of the power balance. As one insider puts it, the DUP are 'hard as nails' and the 'best negotiators' in politics. This is shown by the fact there is a written agreement to begin with. When concerned MPs questioned whether it was such a good idea to have an agreement in writing, it was relayed that the DUP had requested this – and that was that.

That document is expected to include a list of bullet points - stating what the DUP will vote with the government on and what it will not. On the 'yes' list is Brexit and anti-terrorism measures, and on the 'no' list are any austerity measures.

However, the DUP are not done yet. Just as Tories thought they were coming to a final agreement this week, more issues arose. While money is a constant factor, one source says the DUP suddenly brought up the issue of parades. Given that this relates to the Orange Order, any concession from the Conservatives could be in breach of the Good Friday agreement.

The general consensus is that an agreement will be reached but it could come at a price not worth paying.