Obviously he hadn't read his North:
It was Ted Heath, a Tory (theoretically), who took us in (after the ground-breaking by Macmillan), it was the darling Thatcher who led the "yes" campaign for the Tories in the 1975 referendum, and it was she that agreed the Single European Act.North has duly torn into Oborne's revisionist tosh.
Then, of course, it was little Johnny Major, Thatcher's protégé, who negotiated the Maastricht Treaty (aka Treaty of the European Union) – and wrecked the Conservative Party getting it through the Commons. Now the heir to Heath, the fabulous Mr Scumeron, refuses us a referendum on the Lisbon treaty and gives us AV instead.
Oborne must know it is tosh, so who fed him the line (and was lunch nice?)? It must have been a Tory, but why?
Anyway, the issue is not why do the Tory high command want to pretend they're eurosceptic. It's not even is euroscepticism important to the Labour front bench. (Answer: probably just to a means to an end, a chance to bash the government for failing in goals they know they can't meet because the powers have been signed away. If the Tories implausibly turned anti-EU, Labour would resurrect the cry of Little Englanders.)
The issue isn't even why is Oborne so venal.
The "£400 a family" is in the news, so the Tories are confident they can shake this stick with no serious worry about a eurosceptic party. Of course they are right.
Farage drives people who are better than him out of UKIP, which leaves it very low quality. Luckily for him, when they leave UKIP they seem to leave politics. The disaffected MEPs show no sign of putting together a True Finns or a UKIP mark two, and the much touted South West disaffection continues to be just grumbling.
And so the Tories can pretend to be eurosceptic in what Oborne would probably call utter security.
Someone should give them a fright.