This is highly uncertain. Experts at UK in a Changing Europe told us that, under international law, it’s not clearly set out that the UK has to pay anything once it has left the EU. However, the EU would be within its rights to take the case to the International Court of Justice. The grounds for this would be the UK’s repeated commitments to pay—this was set out most importantly in the Joint Report of December 2017, which set out principles on a number of issues in the negotiations.
The European Commission said in a statement on January 30 that “the UK would be expected to continue to honour all commitments made during EU membership” in the event of a no deal scenario.
In addition, UK in a Changing Europe told us that the UK might consider the reputational damage caused by not paying the divorce bill, just as it is about to try and negotiate new trade deals with other countries. It might cause other states to question whether the UK’s word is worth as much as it claims.
This article is part of our Ask Full Fact series on Brexit, answering your questions about Brexit and the latest negotiations between the UK and the EU.