The Conservatives may start slating Gordon Brown for not calling an electon, but there is a difference between considering and going back on one's word.
There is more to this than just posturing. Right now we have been dealing with various crisies during the summer and whilst they are managable, to call an election now would be irresponsible. Government is there to conduct the affairs of state, not just attacking the opposition.
In any case now we shall see if the Tories can hold a united front, as Donal Blaney showed in his recent post on Conservative Home