So the pro-Britain in Europe campaign moves into a different phase today, with M and S former boss Stuart Rose fronting up a collection of business people and politicians who have the considerable task of challenging the tons of anti-European propaganda that has been thrown our way for years.

I wish them luck. Unless David Cameron completely screws up his negotiations, I will be voting Yes, because I have no doubt whatever that Britain’s future is best secured as a strong member of the European Union. Equally for us to come out of the EU will be to reduce us further as a political and economic force in the world.

But I confess to being somewhat worried about the debate, not least because it is Cameron who is in charge of those negotiations, and because he only agreed to the referendum in the first place to get himself out of a hole of UKIP and the Tory Right’s making. There is nothing he can gain from Angela Merkel, Francois Hollande, Jean-Claude Juncker or or anyone else that will satisfy these people.

So the aim for Rose et al has to be to focus on those in the middle ground – not people like me who fail to foresee the circumstances in which I would vote to come out, nor people like Nigel Farage and the sizeable number of Tory MPs who will vote to get out, come what may.

Here we have to trust the good judgement of people to see and hear their way through the wall of noise that this debate will generate. Most of the print media is stacked against Europe and they will continue with their lies and distortions which will be picked up by anti-MPs as fact and which will also frame much of the way the broadcast media cover the referendum when it comes.

Indeed, even the fact of having the debate is already harming Britain’s strength and standing in the world. I have been travelling a fair bit of late, and usually try to see senior political figures wherever I go. And it is frankly alarming the extent to which in Europe in particular, Cameron is now seen as something of an irrelevance when it comes to the really big issues like Syria, the migration crisis, or Ukraine. One EU leader told me ‘all he cares about is his referendum, and he doesn’t care if everyone knows it.’

It was similar in America last week. His conference speech got a bit of coverage on the inside pages of the major broadsheets, but for many Americans, there was Thatcher and there was Blair and they are not terribly sure who is there now.

This matters. One of the jobs of world leaders is to be inside the heads of other world leaders when they are making decisions or formulating their foreign policy. ‘What will Angela think?’ tends to pass through the minds of most of them. ‘What will Putin do?’ is these days asked more than ever. ‘What will Cameron think?’ … this comes some way down the list, and that is bad for Britain.

Of course if he bows out on the back of a winning referendum, having won a Commons majority most expected him not to win, he will be able to say he has succeeded, politically. But Britain is not the force it was, and Cameron’s relative disinterest in the world outside, matched to this referendum now absorbing most of the energy he can devote to ‘abroad’, is likely to accelerate that trend.

The sensible people who want to keep us in Europe must guard against complacency. Referendums can often go wrong for reasons which have nothing to do with the issue in hand. The propaganda campaign will be relentless. Also, I am not sure I trust Cameron not to slither to the wrong side of the argument if he feels it is heading that way.

I was worried when I read a few months ago that he wanted business to hold fire on the pro side until he had his negotiation ducks in a row. Well, he doesn’t, and yet the campaign is under way. The first is a bad sign. The second is a good sign. The campaign must be fought as hard as the other side intend to, which is very hard indeed.