Dear Boris,

You and I are friends, despite being on the opposite sides of the great political divide of our generation. But what does our friendship mean?

Of course, there’s affection. That has deep roots, going back almost half a century when we were at school together. But for the past three and a half years, we’ve grown distant. Perhaps that’s not surprising. Your project is Brexit; mine is to stop it. I’ve spent virtually every waking hour in recent years campaigning to stay in the EU.

How will it help you if our proud nation is bullied in turns by the US, China, Russia and the EU?

I still feel we could have debated Brexit more in recent years, as we did before you crossed the Rubicon. But you haven’t wanted to engage. The few times we have met since early 2016, you largely avoided the topic. It was almost as if you were afraid of contamination – that I might sow doubt in a fragile conviction that Brexit was best for the UK.

Now that you are on the brink of power, I have been thinking about loyalty. Aristotle’s idea that virtue is the mid-point between two vices is relevant. One vice is treachery. The other extreme is blind loyalty, backing somebody even though you think they are doing the wrong thing.

So, true friendship, perhaps, is being loyal – and not joining in the attacks on your character I see everywhere today. But it’s not blind loyalty. It’s helping a friend achieve what’s really in their interests even if that’s not what they want.

Is it really in your interest to crash out of the EU without a deal? Or, failing that, will it really be good for you to put lipstick on Theresa May’s pig of a deal – which you rightly said would turn us into a vassal state?

How will it help you if our proud nation is bullied in turns by America, China, Russia and the EU – and we have to suck up to Donald Trump because we’re so desperate and friendless?

You’re no fool. You must see that we are becoming less, not more powerful. The only explanation I can give is that you have a tiger by the tail and can’t let go.

I’m trying to tranquillise the tiger because it’s about to devour our country. But doing so may also be in your interests. You will then be able to let go of its tail.

You love Churchill. You must know one of his favourite poems, The Clattering Train. The last verse goes: For the pace is hot, and the points are near,/ And sleep hath deadened the driver’s ear;/ And signals flash through the night in vain./ Death is in charge of the clattering train!

You’re like that driver on the clattering train, except you’re not asleep. Jacob Rees-Mogg and Nigel Farage have persuaded you to sabotage the brakes – and you are hurtling towards the abyss with 66 million people in the back. So some of us are going to have to stop the train for you.

Like you, I’m a fighter. But I don’t want to fight fire with fire. I prefer to fight fire with water. I prefer Gandhi to Machiavelli. The ends don’t justify the means. If we pursue the wrong means, we’ll corrupt the ends. Democracy so easily descends into demagogy, as the ancient Greeks knew so well.

It’s great to be ambitious. But as you stand on the verge of Downing Street, I ask you to reflect. What do you want power for? Surely, it’s to fix the country’s real problems such as lack of investment in large parts of the country, care for our ageing population and knife crime. Isn’t it also to use our influence in the world to fix global problems such as the climate crisis?

And can’t you see that we’ll be much more able to do these things if we stay in the EU? We’ll have more money, more power and our politicians won’t be obsessing about the fallout from Brexit for years. We have to put the bawling Brexit baby to bed.

It is not too late to change course. But I’m not counting on that. You’ll probably try to rip us out of the EU without a deal and, when MPs stop you, call a referendum or an election. At that point, pro-Europeans have to win the argument. So much is at stake. That’s why I will be going to the grassroots demo in Parliament Square on Saturday and saying: “No to Boris, yes to Europe.”

• Hugo Dixon is chair of InFacts and deputy chair of the People’s Vote campaign