Setting a deadline

Mrs May has come in for a lot of criticism for proposing to fix the exact date of Brexit. The nub of the objections is that this prevents flexibility - what if the agreement is almost done but just needs a couple more days? Forcing Brexit at that point would be sheer lunacy.

What the objectors fail to understand is that an inflexible deadline can actually work in a negotiator's favour - as does a believable willingness to walk away with nothing. The point is that you are betting that the other side prefers some deal to no deal. A deadline means they can't use the strategy of wearing you down, they need to focus on what they really want and concede things you really want.

If some deal is 'still two days away' but the deadline is midnight tonight then everyone goes all out to sort it before the final stroke of twelve, working through the night. This is how company mergers and acquisitions are run.

So Mrs May is doing the right thing?

What Mrs May doesn't understand is that a deadline only works if you are absolutely clear about what you must have in the agreement and what you can concede. If you don't know that but your opponents do then a deadline gives them the advantage.

Even if Mrs May ever decides what she is aiming for and is confident that the rest of the EU will agree to it, then she still isn't strong enough to set a deadline. This is because the 'no deal' threat is not credible from our side.

Ironically it is a credible threat from the EU side, though they are far too experienced to bandy it around like our Brexit headbangers do. Every delay the EU negotiators introduce is a subtle reminder that 'no deal' is a very bad deal for the UK, but not all that bad for the EU (bar Ireland which would take about half the damage we will).

Mrs May should forget messing about with deadlines and focus on sorting out her cabinet and sorting out her Brexit plans.