Boris Johnson described protesters from Extinction Rebellion on Monday night as “uncooperative crusties” occupying “heaving hemp bivouacs” on the streets of Westminster.

At the Extinction Rebellion protest site on Trafalgar Square on Tuesday morning, Nicola Hargreaves snorted as she considered the prime minister’s remarks. “I’m a solicitor,” she said. “And I’m dressed in clothes from Whistles that I’m pretty sure don’t have any hemp in them at all. So Boris can shove his comments up his arse.”

Nicola Hargreaves: ‘Boris can shove his comments up his arse.’ Photograph: Damien Gayle/The Guardian

Disbelieving when told where the prime minister had been speaking – at the launch of a biography of Margaret Thatcher, which he advised the protesters to read – Hargreaves, 50, added: “It makes me half angry, and half I laugh at him because he’s so ridiculous, he’s devolved from reality.”

The XR protests are not without the sort of veteran environmental campaigners who might align with Johnson’s caricature. But a distinguishing feature of this campaign has been the participation of people who might in the past have stayed at home.

Alex Burton: ‘There’s so many average people who never imagined getting involved.’ Photograph: Jill Mead/The Guardian

Hargreaves, an ordinary member of the public who washes on a regular basis, was far from alone. She was standing at the south end of the square with Hazel Mason, 70, an actor, and Paul Smith, 46, a learning disability nurse, all of them from Barnet. A few yards away in the driver’s seat of a hearse blocking the entrance to Whitehall sat Alex Burton, 35, a librarian from Tufnell Park.

“The two people I came down here with to get arrested are both women in their 60s who live in Muswell Hill,” Burton said. “They are about the furthest possible from that comment. I would say the best thing about the movement is that there are so many mums and older people … there’s so many average people who never imagined getting involved.”

Nick Onley: ‘Boris is wasting his talent on the wrong target.’ Photograph: Jill Mead/The Guardian

Nick Onley, 57, in the passenger seat next to Burton with an unfastened D-lock around the headrest, said Johnson’s description was hilarious. “It’s just a shame that he’s wasting his talent on the wrong target,” said Onley, a community music teacher from Stamford Hill.

Beneath them, locked to the underside of the hearse, sat Inigo Roberts, 21, a barman and fine art student at Chelsea College of Arts. He wasn’t quite sure what a crusty was but he seemed satisfied with the explanation that they were something like hippies with Dr Martens boots and dreadlocks.

“Hippies are an important part of XR,” Roberts said. “We love hippies but we are not all hippies. Whenever it’s been used towards me it’s as an insult … it’s a word that I don’t really understand any more. It’s just such an old term, it’s lost all meaning.”

Edward Freeman: ‘We are not smelly, we’re not crusties.’ Photograph: Damien Gayle/The Guardian

Edward Freeman, 28, a medical student, called Johnson’s comments disgusting. “We are protesting for our future, so we have the right to be here,” he said. “We are not smelly, we’re not crusties, we’re protesting so this planet doesn’t burn to death.”

Freeman, who was in a wheelchair, was particularly angry because he said police had prevented XR from bringing in equipment to make the protest site properly accessible for disabled people. He had had to pay for a hotel to stay the night because there were no tents that could accommodate him. “I was even told to go home by a police officer,” he said. “It’s shocking.”

Ro Lavender: ‘It’s not a time to be throwing insults.’ Photograph: Jill Mead/The Guardian

On Whitehall, closer to Johnson’s 10 Downing Street squat, Ro Lavender, 60, from Leatherhead, said she didn’t think she had ever met a crusty, at XR or anywhere else. “I’m a professional 60-year-old woman with a passion for the world and a passion for people,” said Lavender, a nurse who counsels victims of antisocial behaviour. “The point is that there is a climate and ecological emergency and we would like to speak to him about how together we can turn this around for the next generation. It’s not a time to be throwing insults, it’s a time to sit together and find a solution.”

Rachel Wiggans: ‘He’s across the road and he won’t engage with us.’ Photograph: Jill Mead/The Guardian

Rachel Wiggans, a 64-year-old retiree from Oxford, said Johnson’s outburst exposed his intellectual bankruptcy. “I just think that he is an intelligent enough person to know that if someone presents you with a coherent argument and you can’t win then you abuse them,” she said.

“He’s across the road and he won’t engage with us. We are social workers, we are teachers, we are nurses, we are doctors, we are so-called hardworking families, respectable people. And he can’t respond in a coherent intelligent way to what we are saying.”