Humiliation awaits country walks away

for that? I say: don’t risk it.

Second, Britain’s place in the world is also at stake in this referendum.

I’ve been Prime Minister for six years. And I can tell you: Britain is a stronger force in the world when we’re working from the inside as part of the world’s most important organisations. Whether it’s the UN, Nato or the European Union, we have a seat where it really matters. When we want to effect change in the world – whether to advance our national interest, protect the security of our people or alleviate suffering in the world – the levers we reach for are invariably found within these organisations.

If we leave the EU, it will still be a very important forum for sorting out the biggest problems that affect Britain. The difference is: we just wouldn’t be there. It will still take decisions to tackle terrorism, climate change and migration. We just wouldn’t be in the room when it happens.

In fact, the first thing we’d do if we left is establish a huge diplomatic operation to lobby EU countries before their meetings happened, and then spend weeks afterwards trying to find out what on earth had happened, and how it might affect us.

It would be a one-off and permanent diminution in our standing in the world; an abject and self-imposed humiliation for a proud and important country like ours. That’s why all of our major allies want us to remain; only our adversaries want us to leave. I say: we are not one 28th of the EU; we are one hugely important, global player. And that is exactly how we should stay.

Finally, there is this question about the kind of country we want to be. I’m so proud of Britain – this open, tolerant, big-hearted country of ours. But I believe this referendum has now become a watershed moment for our country. And we are going to have to make a defining decision on Thursday: ‘If we were to leave and it turned out to be a mistake, there wouldn’t be a way of changing our minds’ are we going to choose Nigel Farage’s vision – one which takes Britain backwards; divides rather than unites; and questions the motives of anyone who takes a different view? Or will we, instead, choose the tolerant, liberal Britain; a country that doesn’t blame its problems on other groups of people; one that doesn’t pine for the past, but looks to the future with hope, optimism and confidence? I think the answer will determine what our country feels like for a very long time.

Of course, the EU is not perfect. But in a way, our membership of it is the fundamental expression of our Britishness – outward-looking, compassionate, engaged – and yes, sceptical, too.

So much is at stake on Thursday. And so rarely will we ever make a decision of such magnitude. And here’s the thing: it’s irreversible. There is no turning back if we leave. If we choose to go out of the EU, we will go out – with all of the consequences that will have for everyone in Britain. And if we were to leave and it quickly turned out to be a big mistake, there wouldn’t be a way of changing our minds and having another go. This is it.

So ask yourself: have I really heard anything – anything at all – to convince me that leaving would be the best thing for the economic security of my family? Is walking away really in keeping with the important, influential country that Britain has always been? Is leaving going to build the kind of open, compassionate country I want my children and grandchildren to grow up in? And if you’re not sure, don’t take the risk of leaving. If you’re not 100 per cent persuaded, there’s only one place to put your cross. If you don’t know, don’t go. Instead, vote to remain on June 23.