Since Donald Trump took office, a wave of protest has swept across the world, first with the Women’s Marches and now with protests in the UK against Theresa May’s apparent acquiesence with Trump’s ugly, racist, proto-fascist policies. While one hesitates to say “look on the bright side”, it is at least encouraging to see so many people so engaged.

What so many people are pointing out is that these marches are not made up of your usual suspects: the demographic is totally different to the usual assortment of activist groups, trade unionists, campaigning organisations and people who just like placards and shouting.

The anti-Trump movement is organic, spontaneous and inclusive. So of course, the hard left want to get their hands on it. And when the hard left gets its hands on something, that thing is doomed.

At Monday’s London rally at Downing Street, the red flags of the Socialist Workers Party were already in evidence. “Stand Up To Racism”, a front for that party, is attempting to organise another demo at the US embassy in London on Saturday. Like that other SWP front, Unite Against Fascism, and of course the Stop The War Coalition, Stand Up To Racism has taken for its name a phrase that is almost entirely unobjectionable. This makes it easy to pull in support for its marches and petitions.

But a bit of scepticism is crucial here. Stop The War is a discredited organisation run by sinister apologists for the Assad and Putin regimes. Their newspaper of choice, the Morning Star, celebrated the “liberation” of east Aleppo by Assad’s forces, and defamed the heroic White Helmet civil defence group as jihadists. They count among their leading lights such charmers as Stalinists who have declared solidarity with North Korea.

And then of course there is the charming George Galloway, a patron of the Stop The War Coalition, who wrote of Trump’s victory “I don’t care what they do in their own country, just as long as they don’t plunge us into more wars. If they want to build a wall that’s up to them. If they want to throw out illegal immigrants or keep out Muslims that’s up to them. It’s their business.” Galloway, lest we forget, also shared platforms with Nigel Farage while campaigning for Brexit.

Read more about them here, and here.

And then there is the Socialist Workers Party, a cultish organisation that defended one of its senior members against rape allegations and defamed the alleged victim to her party comrades.

These people and their fellow travellers are simply opportunists, hoping to harness the righteous energy of thousands of people and then strangle it with their own stupid, moribund sectarian politics. The one advantage they have is that they will always turn up, hand out the placards and lead the chants. They are professionals at this stuff. But make no mistake: they will destroy everything that is positive about the current movement. They will loudly proclaim that this is their movement: they will set up committees that they will then dominate through sheer bloody-mindedness. They will eventually drive well-meaning people away with their aggression and obtuseness.

So let’s not let them get their hooks into the anti-Trump protests.

Do not sign their petitions; do not hold their placards, do not buy their papers.

Tell them this is a march for liberal democracy, not for their tired, dead, sloganeering.

Do not cheer their speakers. Better still, talk or even sing or clap over them.

These people do not build movements – they wreck movements.

Let’s not let them.