David Cameron is starting a tour of European capitals as a bill paving the way for the UK's EU referendum is launched in the House of Commons. The British PM will attempt to persuade the Dutch, French, Polish and German premiers to back his changes to the UK's EU membership.
The EU Referendum Bill will confirm the question to be put to voters: Should the United Kingdom remain a member of the European Union? The vote will take place by 2017.
The referendum bill was announced as part of a packed legislative program in the Queen's Speech, which also included an increase in free childcare, an income tax freeze and the right-to-buy for housing association tenants.
Downing Street said the draft law's first reading in the Commons was a concrete step towards settling the debate about the UK's membership of the EU.
PM Cameron has pledged to renegotiate the UK's relationship with the EU before holding the referendum, and has vowed to visit all 27 other member states ahead of a summit in June.
First up are Dutch Prime Minister Mark Rutte and French President Francois Hollande, followed by Polish Prime Minister Ewa Kopacz and German Chancellor Angela Merkel.
PM Cameron has called for changes to EU migrants' welfare entitlement, while some Conservatives also want the primacy of British law to be reaffirmed. The PM has hinted he could vote to leave the EU if his requests are not granted, saying he rules nothing out.
Downing Street said the choice put to voters should not be on the basis of the status quo but on a reformed relationship with the EU that the PM is determined to deliver.
But some member states have questioned the need for any change to EU treaties, and ruled out any watering down of the key principle of freedom of movement.
Responding to the Queen's Speech, Labor's acting leader Harriet Harman said her party would back the referendum bill.
Outgoing Lib Dem leader Nick Clegg warned against complacency and called for PM Cameron to lead the bid for Britain to stay in the EU with conviction.
UKIP leader Nigel Farage said the wording of the referendum question was simple, straightforward and unambiguous. He added: However, that Cameron is opting to give the pro-EU side the positive 'Yes' suggests strongly that his negotiations are so much fudge.