DUP deal on 42 day detention?

Our Kingdom has a thoughtful piece on the historical evidence of Westminster deals, that the DUP appears to be banking on breaking. Also interesting analysis on why the DUP, on their own terms, don’t need to do it:

If (Peter) Robinson is to be believed, there is little reason for such a fateful deal, because his party already has an effective veto over devolution(of policing and justice)