We are in the middle of a battle for Britain’s soul. On one side are those who want our country to continue to be forward looking, open to the world, tolerant, inclusive and progressive. On the other, those who want to pit our communities against each other, undo the social progress painstakingly made over decades, and who advocate a politics of division.

Across the globe, the far right is on the rise. They are gaining ground and winning power and influence in places that would have been unimaginable just a few years ago.

Many are using the same methods from the old far-right playbook. Picking on minority communities and the marginalised in order to manufacture an enemy. Fabricating lies in order to stoke up fear. And promoting hatred of immigrants, sympathy for white nationalism, attacks on women’s reproductive rights and rolling back the progress made on LGBT rights.

Take Donald Trump who, as US president, said there were “very fine people on all sides” when white supremacists marched through the streets of Charlottesville. Viktor Orbán, Hungary’s prime minister, has embraced antisemitism and attacked LGBT rights and press freedom. Matteo Salvini, deputy prime minister of Italy, has repeatedly attacked migrants. And Marine Le Pen finished second in the last French presidential election on an anti-immigration platform. Worryingly, similar nationalist and populist parties are gaining support in almost every European country.

Depressingly, here in the UK the Conservative party has not been immune to this far-right virus – and is incapable of fighting it on behalf of the British people. Think about Boris Johnson describing Muslim women as “letterboxes”, Sajid Javid singling out “Asian” child-grooming gangs, Zac Goldsmith’s campaign in the last London mayoral election – widely condemned as Islamophobic. Given where the views of a significant section of the party’s membership lie, I fear the successful candidate in the forthcoming Conservative leadership election will have no choice but to appease these voices to win.

And now we have the Brexit party. Don’t be fooled – it might seem new, but it’s led by the same people who have long deployed deeply xenophobic and divisive rhetoric to advance their cause – regardless of the catastrophic consequences for communities and our country.

Nigel Farage embodies a strain of destructive far-right politics – masquerading as anti-establishment populism – which has poisoned our national discourse and unleashed a torrent of lies, division and hatred within our society. He promises impossibly simple solutions to incredibly complex problems and, rather than addressing people’s concerns, he preys on their fears.

I support the need for a public vote on Brexit as the public must have the final say

That’s why so much is at stake in this week’s European elections. They are not just about who represents us in the European parliament, but about the kind of country we want to be. Either we listen to Farage’s siren calls and send a contingent of extreme far-right MEPs to Brussels, or we stand up and say enough is enough: this is not the British way.

At a time when our country is terribly divided, the last thing we need is parties in power who would make these divisions worse. These divisions didn’t just appear on 23 June 2016. Yes, the referendum opened the floodgates but the deluge it was holding back had been gathering for some time. In reality, it had little to do with our membership of the European Union, but was more about deep-seated inequality exacerbated by a decade of grinding austerity that has left many cynical about traditional politics and earning less than they did in 2008.

It is no secret that I am a passionate European who believes our future prosperity is better served within the EU. I support the need for a public vote on Brexit as the public must have the final say. It’s the only way out of the mess the Tories have created. When we get a referendum on the final deal, I will campaign day and night for Britain to stay a member of the EU – to protect opportunities for the next generation.

Voting for the Brexit party will not heal our divisions, it will only widen them. We must stand united in our opposition to the far right and reject their dystopian vision of our future. Labour is the only party that can beat them. Voting for smaller parties just makes Farage’s job easier – and makes it more likely that we wake up to headlines proclaiming him the winner – securing the legitimacy of his destructive views.

That’s why I urge everyone to vote Labour on Thursday. We cannot allow the far right to sneak in by the back door. We must stop Farage in his tracks – along with everything he represents. Only Labour is capable of doing this, and of sending the uncompromising message that we are a tolerant, inclusive and forward-looking nation, which rejects the politics of fear, hatred and division.

• Sadiq Khan is mayor of London