The CBI has put out a paper saying the benefit to the UK of being in Europe is between 4% and 5% of UK GDP, or between £62 billion and £78 billion.
So that's it, then. Nice and precise, these are the guys who know, question answered.
Unfortunately it's drivel.
The figure was taken from a digest of other figures which are themselves dubious: many decided on what the answer was and set out to prove it.The CBI itself has always been vigorously in favour of the European ideal and not so long ago was telling us we would be tragically left behind if we didn't join the euro. We're not hearing too much of that any more.
And there is no analysis of what would happen if we left: the savings in the contributions we make, the elimination of swathes of bureaucracy, just the stale, idiot assumption that Europeans would no longer buy our goods even though we bought plenty of theirs.
Much of what you read about the European debate is rubbish, but if it comes from the CBI, assume it's 100% wrong.