Frans Timmermans, the President of the Party of the European Socialists and a candidate to become the next European Commission president, suggested on Wednesday that the UK should “cool down and rethink” Brexit.

Timmermans' comments came just as the latest YouGov poll suggested that the pro-Brexit Party of Eurosceptic firebrand Nigel Farage could smash the Conservative list by gaining a 27% share of the vote in the European elections set for 23-26 May.

The Tories are polling at 15%, a hist...