Dear Jeremy Corbyn,

The words “j’accuse” have probably been overused since Émile Zola used them in his open letter to the French president, Félix Faure, on the Dreyfus affair. They are, however, appropriate when somebody in authority is failing to do what is right, and so I make no apology for using them in this open letter to you.

Mr Corbyn, I accuse you of failing to do your duty by not opposing in any real sense our government on the most important issue of our times – Brexit.

Historically, some of our worst mistakes have been made when the opposition has failed to question and stress-test the policies of the government of the day

The Brexit motion passed by Labour party conference in September included a clear commitment to “support all options remaining on the table, including campaigning for a public vote”, should the party not be able to secure a general election.

Party policy also dictates that your party should endorse a future relationship with the EU that “guarantees full participation in the single market”. Our democracy only works when the official opposition does its job of opposing the government of the day and offers a clear alternative vision for our country, including giving a voice to the voiceless. An opposition that won’t oppose paralyses our political and democratic system.

Historically, some of our worst mistakes have been made when the opposition has failed in its fundamental duty to question and stress-test the policies of the government of the day, and I believe historians will one day look back on the Labour party under you, Mr Corbyn, and ask a simple question: why did you sit on the fence right from the start? Why did you leave it to me, as a private citizen, to question the unlawful use of the royal prerogative to trigger article 50? Your membership, the vast majority of young Labour voters and the unions, are overwhelmingly opposed to Brexit because the European Union is, I would submit, the most successful union of our time. Brexit will lead to a flight of talent, money and taxes – and the country will have to take on more and more debt. It will of course hit the middle classes, but it will be the poorest and weakest in our society – the left behind, who depend on the NHS, social housing and foodbanks, and so many other public services – who will be its greatest victims.

I had been a member of the Labour party until your non-position on the greatest issue of our times became apparent. It breaks my heart to have to write to you in this way, but you have given me no alternative. David Lammy, one of your most principled Labour MPs, said in an emotional speech last week that if you did not now lead the campaign for a people’s vote, Labour would be kept from office for a generation.

Here’s what the people’s vote campaign needs to do | John Harris Read more

I am afraid to say that I agree with him. At least half of the electorate do not have a voice, and the Labour party can and must give them one. You must listen to the growing number of voters saying that this Conservative government’s Brexit course is “not in my name”. Brexit is simply too fundamental an issue to be used by Labour to calculate how to get into power by deliberately enabling chaos. The Labour party should be about doing things not because they are opportunistic or expedient but because they are right.

This is now a matter of what sort of country you wish the United Kingdom to become. One where the union itself is threatened by an ideological rightwing policy. A policy based on building barriers and walls that will take us not forward but backwards. I beg you, as Labour’s leader, to reject a policy that will so obviously turn our country into a laboratory for one of the most extreme rightwing experiments we have witnessed since the 1930s.

Labour argues for article 50 extension if Brexit deal voted down Read more

Theresa May’s deal is worse than the special deal we already have with the EU. Accept the reality that neither you, nor another leader of the Conservative party, can negotiate anything different or better – there isn’t the time and the EU has made it clear they are no longer interested in any more talking. You have the power to both ensure an option to remain is included in the parliamentary meaningful vote, and if this vote results in an impasse, ensure there is a public vote, so the people of the United Kingdom can throw parliament a democratic lifeline to end this chaos.

Respectfully, Gina Miller

• Gina Miller is the founder of endthechaos.co.uk