If all goes as “planned”, the UK will be out the union by the end of March 2019, following the Brexit vote last year.
Who could follow in the UK's footsteps?
William Hill, the only betting company to offer odds for this issue, gives odds of 2/1 for a Greek departure.
Greece has faced numerous economic problems over the years, with many arguing that the country should leave Euro in what has been termed a "Grexit". If Greece fully left the Euro and EU such an exit could be term as a Grexit+.
The second odds-on favourite country to leave the union is Italy, with William Hill giving odds of 5/2.
The fifth odds-on joint favourites are Hungary and Ireland with odds of 12/1 each, followed by the Czech Republic and Denmark, each on 16/1.
Cyprus has odds of 20/1.
All odds are from Oddschecker, and all are accurate as of 24th August.