David Cameron has told the BBC he is “upbeat, bullish and optimistic” that he will succeed in renegotiating the UK’s relations with the European Union.
He said he would “absolutely” give a cast-iron guarantee that a referendum would be held by the end of 2017.
Asked if that meant he would recommend voting to leave the EU if he failed to get the changes he wanted, he said he was confident the talks would succeed.
UKIP’s Nigel Farage accused Mr Cameron of “pretending” to be Eurosceptic.
Appearing on The Andrew Marr Show, Mr Cameron restated his plans to secure changes to EU powers over the UK in areas of immigration, welfare, the single market and the ability of national parliaments to over-rule Brussels.