European Commission President Jean-Claude Juncker has mocked resigning Brexiteers at the European Parliament, saying they are 'no patriots'.

"The ones who have caused this result in Great Britain are leaving the stage one after the other. Johnson, Farage, and others. To be honest, they are retro-nationalists, not patriots. Patriots don't abandon the ship when the going gets tough," Juncker said.

Juncker insisted the EU will not negotiate any terms for the British departure until a new leader formally triggers the withdrawal process and the two-year deadline it sets for a deal. Former London mayor Boris Johnson shocked his Conservative party by abandoning a leadership bid, as many expected him to take over current prime minister David Cameron. Nigel Farage on Monday also resigned as leader of the UK Independence Party.

Comparing Brexit to a divorce, the Dutch Prime Minister stressed that the result of British referendum was a wake up call for reforms within the EU, saying that "to continue with business as usual" would be "the worst possible response".