He who pays the whistler calls the tune

Brexit is going to be very expensive. For example the government is budgeting £1 million a day to prepare for Brexit - this is just for the bureaucracy and ignores structural and ongoing costs such as increased border staff and facilities. Cornwall wants £60 million a year to make up for the EU handouts they won't be getting after they voted to leave the EU. Other regions will no doubt want the same (even if they aren't so hypocritical about it). Farmers want state support to carry on as before, as do all the other Britons who benefit from EU funds.

There will be other costs - crops are right now being left to rot in their fields as there is no one to pick them, there is a critical shortage of nurses, London-based financial services are relocating to the Continent. Not to mention that losing the benefits of EU membership will cost between £19 and £26 billion a year.

Bus-side economics tells us that we will have £350 million a week to pay for all this. Even if this were true it wouldn't go very far.

Given all that, it might seem sensible to try to drive a hard bargain with the EU over the divorce settlement.

The EU has recently asked for another £6 billion to cover pension costs. This is on top of the £47 billion it already wants. Mr Johnson suggests we tell them to "go whistle" for any payments - so be thankful he isn't allowed anywhere near the negotiations. Instead Mrs May and Mr Davis have steadily softened their position on payments.

Why? The point is that we are negotiating for our long-term economic future and time is running out. As Mr Barnier, the EU chief negotiator, said, "I'm not hearing any whistling, just the clock ticking."

If we refuse to pay then we get no deal - and a reputation for reneging on our trade agreements. We certainly couldn't expect the EU to do anything to help make Brexit work. We will be hurting economically for a long time.

If we pay then we get a better deal and a more willing trading partner - a trading partner that currently takes 50% of our exports. The sum we owe is very large, but we can afford it, it will be a one-off hit and we will get long-term benefits from it.

By paying our debts we get what we want from the negotiations. He who pays the whistler calls the tune.