One of the most striking things about the Moonie-eyed, cultish imbeciles gluing themselves to our nation’s arterial highways is their age. Alongside the pronoun-sensitive, Corbynist students found at all BLM/XR protests, at least half seem too old to have a job — if they ever had one, apart from cultivating facial hair and stewing mung beans — and seem astonished that anyone else would want one. The look on their collective faces as irate van drivers for whom time is always money furiously berate them is one of smug bafflement. Why work at all? they seem to ask. Why not just live off the land and daddy’s estate?

Never known for their collective ability to tap into the nation’s psyche, the group remain defiant despite growing hostility and a High Court injunction. Roger Hallam, XR’s founder, who has a veritable traffic jam of vehicles on his organic farm and recently spent four months on a jaunt to Canada, says he would blockade an ambulance even if it meant someone’s death. A shame no-one asked if that included his own.

The group are admirably unapologetic about taking direct action. Speaking outside the High Court, spokesman Liam Norton said: “We cannot imagine undertaking such acts in normal circumstances. But we believe that the reality of our situation has to be faced. The collapse of the climate is happening around us. We face economic chaos and the breakdown of law and order in a matter of years.” Perhaps that is the purpose of the protests: to create economic chaos and the breakdown of law and order now to demonstrate what might happen later if the nation remains stubbornly deaf to reason.

Four bearded professors sat in a square discussing Marxism for three hours

I understand the seductive quality of direct action. As the child of progressive parents (I was conceived at a Socialist Labour League conference in Morecambe, shortly after Gerry Healy asked my 18-year-old working class mum if she’d sleep with him on the Eve of the Revolution), I was dragged to numerous marches. I soon noticed that despite our chanting slogans with the robustly-built women of Greenham Common, and waving placards in support of the miners, no-one appeared to take much notice. US missiles continued to hum in Berkshire bunkers, and miners continued to be extracted from their mines. In fact, it seemed that the papers and politicos were only interested when people starting throwing things, as they did in Brixton and Toxteth in the Summer of ‘81. I took these lessons to heart.

On moving to London in 1985, I got talking to a Scouse political activist outside Tufnell Park Tube. Angry about Thatcher, unemployment, “Yuppies” with brick-sized mobile phones chopping up the planet to snort up their porcine noses? I was amazed that my chippy friend knew me so well, not really comprehending that almost all healthy 18-year-olds feel like just the same. The activist invited me to a meeting, which was disappointing. Four bearded professors sat in a square discussing Marxism for three hours, at the end of which we were given copies of Socialist Worker to flog. Mine went in the bin outside the nearest pub.

Class War were more fun. On writing to the contact address on their outrageous newspaper, several arrived at my door and asked if I wanted to picnic. We walked to Hampstead Heath, where I recall our football match being particularly exciting because there were no rules. Soon I was attending parties at the squatted Libyan Embassy, hanging out with Public Enemy No. 1 Ian Bone, picketing the opening of a new housing development in East London on the grounds it was for “Yuppies”. (This led to my appearing on Page 2 of The Sun because the banner I was holding mis-spelled Hackney).

I soon realised that Class War’s idea of political activism principally involved violence. At a Trafalgar Square demo against apartheid, anarchists began throwing cider bottles without particular aim: one smashed into the face of a teenage girl, who collapsed, howling. At Wapping, where we assembled ostensibly to support the print unions in their Luddite struggle against Murdoch, some of my comrades began chanting sick comments about PC Blakelock, who had recently been hacked to pieces at Broadwater Farm; striking printers told us to go away, or words to that effect.

Is it ever acceptable to vandalise public property?

I began to sense that Class War didn’t have clearly-defined aims, tactics or popular support. Although they turned up when riots were in progress — and in the 1980s there were quite a few — the streets weren’t theirs, the struggle wasn’t theirs and most ordinary people found them a menace. When I went to Belfast and saw the reality of street violence (someone gave me a plastic bullet as souvenir), I realised the English anarchists and far left were mostly Playtime Protesters, harming the very causes they supposedly supported.

Political activism can be seductive, but with rare exceptions (such as the 1990 Battle of Trafalgar Square), it soon becomes counter-productive. As policing adjusts, and the impact of your tactics wane, it’s tempting to up the game, to become more confrontational. Is it ever acceptable to vandalise public property? How about private property? If the police try and stop me, surely I can resist? What about those deluded members of the public who aren’t on the right side? Are they fair game?

I am sure such conversations are taking place within the serried ranks of Insulate Britain, XR, BLM, the anti-vax movement. Within each, I am sure, the hotheads will be outnumbered by the moderates, who understand that defacing Churchill’s statue, closing down public transport and picketing schools, will if anything alienate the very people they are hoping to persuade.

Yet as is so often the case, the loudest voices prevail. Before you know it, you are invited onto television — but only to justify your tactics rather than explain your position. When you are Liam Norton, and not possessed of a rapier-like intellect, you stumble. The public mood sours. There are calls to have you arrested, imprisoned, punished, and you find the backlash bewildering: how can anyone not agree with our cause? Who could be in favour of global warming, racism, injecting kids with “untested” drugs?

This, alas, is the way the world works. As I grew older, wiser, I began to understand that colourful placards, clever chants and hurling bricks, don’t win people over — at least, not enough of the people, enough of the time. If you really want to change the world, you achieve it with reason, words, rational debate. Political activism — or, if you prefer, political violence — can only achieve so much, after which the process becomes self-defeating. That’s something I learned quite young, which is why I find the age of some road-blockers staggering. It is as if in all their years of struggle, protest, fighting the “good” fight, they never listened — never learned.