As things Stand Cameron wanted to have the referendum in the summer but was not able to fit it in with all the regions.
The referendum is coming and it will be foisted on us with as little notice as Cameron can possibly manage. In that scenario the In/Out camps have no option but to bring the debate to us now, before they are faced with a race to the finish where all the issues cannot be brought out and fully discussed.
The cries of "foul" will be thick and fast from either side depending on the result. There is no way this will be presented as fair and given what is happening to Poland right now, Cameron will desperately want to have the referendum over before the EU cracks down and takes power away from the Polish Government. After all, that would play badly in the press during a UK referendum wouldn't it???
Can you imagine the damage a UK election would do where UKIP do to the Tories and Labour what SNP did to everyone in Scotland??