Last Wednesday (before the local elections) he said...
// // The Prime Minister, said that he was prepared to introduce legal safeguards before the end of the current parliament to guarantee that a referendum takes place after the general election. Previously he has promised to call a vote only if he is re-elected in 2015.
The legislation would be designed to demonstrate that he is committed to calling an in-out vote by 2018 after Ukip and other sceptics claimed that his pledge was meaningless. //
And less than a week later he admits...
// The Prime Minister said that his Coalition deal with the pro-European Liberal Democrats means the Government cannot introduce legislation paving the way for a vote on Europe after the next election.
Mr Cameron’s comments on legislation, in a private letter to Conservative MPs, come only days after he dropped a pre-election hint that he was prepared to consider the option. //
http://www.telegraph.co.uk/news/politics/conservative/10042596/David-Cameron-I-cant-legislate-for-an-EU-referendum.html
Why should we believe ANYTHING he says?