The UK agreed to make a series of payments to the EU, as part of the deal when it left in January, often called the divorce bill.

This means the UK would immediately leave the European Union (EU) with no agreement about the "divorce" process.

Some Tory leadership candidates – most notably Boris Johnson – have said they would withhold the £39 billion divorce bill negotiated by Theresa May as a card in order to force the EU to renegotiate the Brexit agreement. Just how practical is this proposal?