David Cameron has given his ­strongest indication yet that he could back taking the UK out of Europe as he spent the first day of his party conference battling the fallout from a defection to Ukip and the resignation of a minister over alleged "sexting".

Senior Tories admitted that the party's week-long pitch to voters, staged just seven months before the next General Election, had got off to a "very bad start".

Within hours the party lost an MP, as Mark Reckless announced his shock move to the eurosceptic Ukip, and a minister, as Brooks Newmark admitted he had been a "complete fool".

One of the central aims of the conference had been to win over voters swinging between voting Tory and Ukip.

There had been reports Mr Cameron would use his keynote speech this week to announce he will argue to take the UK out of Europe if he fails to win enough concessions from Brussels.

Asked about the issue yesterday on the BBC's Andrew Marr programme he said: "I've said this all my political life, I've said if I thought it wasn't in Britain's interest to be in the European Union, I wouldn't argue for us to be in it."

He added: "I'm a deeply ­patriotic politician and person, I do this job because I love my country, I care passionately about its future and I want it to be a strong, proud, self-governing, independent nation."

He also criticised Mr Reckless's actions, claiming it made the defector's ultimate aim - a referendum on the UK's EU membership - less likely by increasing the chances Labour would win the next General Election.

Labour leader Ed Miliband has rejected calls from some within his own party to pledge such a vote.

Mr Cameron has said he will hold a referendum in 2017, but only after a renegotiation of the UK's relationship with Europe.

The Conservative chairman Grant Shapps went further, saying Mr Reckless "lied and lied and lied again" to Tory activists. Voters and donors had been "betrayed" by the MP for Rochester and Strood, he added.

He said: "Two days ago, he was busy leaving phone messages claiming he was enthusiastic about joining us to campaign... here in Birmingham today. He lied and lied and lied again."

Mr Shapps also announced that the Tories would be campaigning "hard" in Mr ­Reckless's constituency.

The MP has announced he will call a by-election to try to take the seat for Ukip.

Another Tory MP, Cabinet Office minister Brooks Newmark, resigned after reportedly sending explicit photographs of himself to an undercover newspaper reporter working as part of a tabloid sting.

According to the Sunday Mirror, Mr Newmark allegedly exchanged pictures with a ­journalist posing as a "Tory PR girl".

The 56-year-old married father-of-five offered his resignation after learning the newspaper was about to publish details of their exchanges.