This morning I wrote to Matthew Elliot, the chief executive of Business for Britain, to resign from his organisation's advisory council, which I have been a member of for the past 12 months or so.
The reason for my resignation is simple: since the Business for Britain declared that it was backing a UK departure from the European Union, and last week effectively morphed into the 'Vote Leave' campaign, I find myself unable to support the organisation due to a direct conflict with my core belief that the UK is, on balance, better off inside Europe than out.
As the Prime Minister said at the Conservative Party conference last week: "We all know what’s wrong with the EU – it’s got too big, too bossy, too interfering. But we also know what’s right about it – it’s the biggest single market in the world."
And for me that's the clincher. There are half a billion people in the EU and that makes up the largest economy in the world. Why would you risk making it harder to get our goods to all of those customers?
In 2014 the UK exported £147bn-worth of goods into the EU and that is a huge amount to risk on a project that seems to me to be founded on the unjustified fear that Europe is taking over our country and our way of life.
The truth is that this can only happen if we allow it to, and retaining our seat at the top trade table, as part of the largest trading block on the planet is part of the way we will remain strong enough to defend the uniqueness our way of life.
Yes, we do need to get a better deal out of Europe for the UK, but special treatment for Britain is something that we have always managed to win, and I can't see why we, and David Cameron, won't win out again by achieving this. After all we have a pretty decent track record, having retained the pound and our border checkpoints, won rebates and avoided bailouts.
That's why I'm sticking with Cameron and Lord Rose, even Tony Blair and Gordon Brown (never thought I'd say that sober) to back Britain by backing the argument that we should stay in the EU. I'm certain that come referendum day people will see that the benefits of remaining far outweigh the reasons to leave.
In fact I think that given that the moment for greater European political union has well and truly passed - even the French and Germans have given up on that one. I think it's almost Britain's duty to stay and fight for the union's economic value, while slowly dismantling the Brussels bureaucracy.