A leading Conservative backbench MP says he will try to force the government to hold an early vote on whether Britain should leave the EU.
Windsor MP Mr Afriyie – once the subject of leadership bid speculation – said the public was “not convinced” Prime Minister David Cameron would stick to his pledge of a vote if the Conservatives win the general election in 2015.
Home Secretary Theresa May followed Number 10 in slapping down Adam Afriyie’s plan to table an amendment to legislation, which paves the way for a promised vote in 2017.
Writing in the Mail on Sunday, Mr Afriyie said delaying posed “significant dangers”, including building support for the UK Independence Party (Ukip) – a serious concern for many colleagues and activists.
He claimed the support of “many MPs from across all the main parties” for an early referendum.
But with Number 10 insisting Mr Afriyie’s amendment would not be allowed to pass “in any circumstances”, Ms May she thought Mr Afriyie had “got it wrong”.
She added it could pose a threat to James Wharton’s government-backed private members’ bill.
Mr Wharton’s proposal aims for a referendum in 2017 to give the UK time to renegotiate the terms of its EU membership.
Ms May told BBC1’s the Andrew Marr Show: “I think what is crucial is that we have at the next election a Conservative party that will be offering people a renegotiation, a new settlement with Europe, looking to the future and then putting that to the British people in an in or out referendum.
“What the amendment possibly could do, as James Wharton himself who put in the referendum bill through parliament has said, is it could actually jeopardise that bill.”
A Number 10 spokesman said of Mr Afriyie’s plan: “The PM will not let it stand.”
Tory MP Mr Wharton, who is attempting to steer his leadership-backed legislation through parliament, said Mr Afriyie’s move would delay and even “kill” his private member’s bill altogether.
He said: “This amendment would make it far more difficult to navigate the challenging procedural hurdles we need to overcome and I hope its sponsors might rethink their approach.
“We need to build as broad a base of support for the bill as we can if we are to get it through parliament and the policy of a renegotiation, followed by an in/out referendum, is the right one to do that and the right one for the country.
“I hope MPs will decline to support it as the ultimate impact might well be to kill my bill, which would only help those who don’t want any referendum at all.”
The European Union (Referendum) Bill easily cleared its first Commons hurdle in July after Labour and the Liberal Democrats stayed away.
Ed Miliband and Nick Clegg have dismissed the bill as a stunt designed to shore up the prime minister’s position with his rank and file – pointing out that it has virtually no chance of becoming law.