He led the campaign to stay part of the EU and will step down in october.
He said the country. needed "fresh leadership".
Less certain is the plight of the 3.3 million non-British EU citizens living in Britain,and the 1.3 million Britons living in other EU countries.
others may follow the UK's lead in exiting the EU.
Representative from Holland's Dutch Freedom Party and France's National Front Party said : Now it is our turn