So talking to the Mr last night about this, well sort of it started as a cheery topic of "civil war won't break out here we are not the French!" as I was saying, (say what you like about the French if something rattles their cages they are organised enough to kick off wish we had some of that spirit here) and it got onto the topic of this brexit fund, as this money is for law and order really as the Mr is convinced that if the scales tip too far civil war will break out here.
So this money is basically to pay for things that we don't currently need like customs, border control and more policing in case riots break out. This is what it is coming down to.
He did sum up a series of possible theoretical events which could lead to this eventually.
"So what do we do if civil war does break out then?"
"Leave the country"
The French just would not allow this to happen they would kick off and destroy Paris to demand that Article 50 be revoked, whereas the British will complain a bit and hope for the best whilst the Government takes us down a path of no return, well no easy return.