But we also have a fantastic opportunity to march in favour of a positive vision for our country. In favour of a fair and open society, and in favour of honest politics.
Yes, there is a lot to fear about Brexit. But project fear is not enough. We also need project hope.
This positive vision should be partly about how our EU membership is good for the four “Ps”: peace, power, prosperity and people.
Brexiters used to mock us when we said the EU was a peace project. The end of the Second World War seemed too long ago to matter. The fall of the Berlin Wall and the end of fascism in Spain, Greece and Portugal seemed too far away.
Now we can see how being in the EU underpins peace here and now – in Northern Ireland. It’s because both the UK and the Republic of Ireland are EU members that there are no borders on the island of Ireland or in the Irish Sea.
Brexiters used to cry: “Take back control!” What a hollow slogan that is when the prime minister’s deal turns us into political eunuchs, following so many of Europe’s rules without a say on them.
We have been one of Europe’s most powerful countries – and could still be. We have helped shape the EU’s policies on everything from tackling global warming and terrorism to standing up to Vladimir Putin. We have used our power in Europe to have greater influence on the world stage.
The Brexiters used to boast that we’d be cutting new trade deals across the world with the swagger of a latter-day Walter Raleigh. Instead, we have the pathetic sight of Liam Fox begging Donald Trump’s minions to thrust chlorine-washed chicken down our throats.
EU membership underpins our prosperity. It has a vast single market that we have done so much to create. It has dozens of trade deals from Canada and Japan to Switzerland and South Korea. Because the EU is the world’s largest economic bloc, it has negotiated good deals where we don’t get bullied – and we played a leading role in clinching them.
Some Brexiters have a blithe disregard for people’s interests. Some are climate change deniers. Some want to slash rights for women, workers and consumers. Others just want to shut foreigners out of our country.
But the EU is good for our people. It underpins our rights. It has created a large open space of opportunity – in which we can live, work, love and retire. This is part of what excites so many young people.
So peace, power, prosperity and people. This is what the EU is good for and we need to march for this on Saturday.
But that’s not enough. The four “Ps” fire up some sections of our society, but leave others cold.
What have they got to do with the troubles they face in their daily lives? Proud communities that have suffered from decades of deindustrialisation. Powerlessness in the face of globalisation. Politicians who don’t seem to care.
An NHS at breaking point. Lives that seem meaningless.
These are the country’s real problems – and in some cases, they led people to vote for Brexit.
A message about how the EU is good for us doesn’t cut much ice with them. When life is dreary or worse, saying we should keep things just as they are comes across as complacent and, yes, elitist.
Those who voted for Brexit because they wanted change were right. Those who campaigned for Remain to keep the status quo were wrong.
But how can we create a fairer society? A large part of the answer is public investment and good policies.
Staying in the EU will not guarantee that we fix the country’s real problems. But we’ll certainly have more money, probably running into tens of billions of pounds a year. And our politicians won’t be so busy fighting about the aftermath of Brexit that they can’t focus on anything else.
There are lots of good ideas about how to heal our divided country if we stay – for example, those outlined by CommonGround. What we need is the political will to implement them.
To get there, we also need a new referendum – and a campaign that is different from the one from three years ago. The more honest it is, the more it will bring the country back together.
When we march on Saturday, lots of negative emotions will be going through our minds: fear, anger, hatred even. But let’s also find room for the positive ones. And with a great roar, let’s demand that MPs put Brexit to the people.
Hugo Dixon is deputy chair of the People’s Vote campaign and co-founder of CommonGround