British ministers voice support for leaving EU

Defence minister Philip Hammond told BBC radio later the same day: "If the choice is between a European Union written exactly as it is today and not being a part of that then I have to say that I'm on the side of the argument that Michael Gove has put forward."

Both men nuanced their statements.

Gove noted that his "preference is for a change in Britain's relationship with the European Union" rather than for leaving the EU.

Hammond said it would be "defeatist" to quit the Union without trying to reform it first.

Their remarks come ahead of a vote next week on holding an in/out referendum more quickly.

Prime Minister David Cameron has promised to hold it in 2017 - after the next elections and after talks on taking back EU powers in areas such as criminal law and social policy.

But two of his MPs have tabled an amendment to hold it in 2014.

The non-binding motion is expected to get just 100-or-so mostly Conservative votes in the 650-seat assembly.

Gove himself dismissed it as "letting off steam."

But it will add to pressure on Cameron to reconsider the 2017 date.

Three Conservative heavyweights - former chancellor Nigel Lawson, former chancellor Norman Lamont and former defence minister Michael Portillo - last week also said Britain should get out.

Lawson wrote in an op-ed that: "The relevant economic context nowadays is not Europe but globalisation, including global free trade, with the World Trade Organisation as its monitor."

He added the EU has "achieved its historic purpose and is now past its sell-by date."

Lamont said on BBC radio: "I think that the economic advantages of the EU are vastly over-stated. I think we could manage on our own, as Switzerland … does."

Meanwhile, huge gains by the eurosceptic Ukip party in recent local elections backed up Gove's claim that many ordinary British people want to leave.

Article 50 of the Lisbon Treaty sets out a protocol for an EU member state to "withdraw from the Union in accordance with its own constitutional requirements."

It says EU countries "shall negotiate and conclude an agreement with that state, setting out the arrangements for its withdrawal" - a clause that would allow the UK to create a free trade zone with Europe.

For its part, the opposition centre-left Labour Party seized on Gove's statement to hammer Cameron.

Its shadow foreign minister, Douglas Alexander, told the Financial Times on Sunday that leaving the EU would harm US relations.

He recalled a warning in January by US diplomat Philip Gordon against holding the in/out vote.

"In doing so he [Gordon] exposed the post-imperial fantasy of Conservative eurosceptics that our relationship with the US is an alternative to our relationship with Europe," Alexander said.

Cameron is visiting Washington this week, with the in/out question likely to come up in his US talks.