Let's face it, for certainly the last 30 or more years, The Sun's been a conservative (note, small 'c') rag; the only reason that they went with Labour in the first place was because a) the Conservatives were so deeply unpopular by '97 that they'd have lost sales by not going that way, and b) New Labour were making Tory-ish noises themselves which made them easier to tolerate. Personally, I think they're just reverting to type, which is hardly surprising. I would say that it's more the case that they're following opinion rather than leading it.