Boris Johnson has dared to cast some mild scorn on the Extinction Rebellion loons.
The demonstrators - who are demanding action on climate change - should abandon their "hemp-smelling bivouacs" and stop blocking roads, the PM added.
Police have already arrested more than 300 people at the start of two weeks of protests by environmental campaigners.
Some activists glued themselves to government buildings early on Tuesday.
Speaking at a book launch, Mr Johnson said: "I am afraid that the security people didn't want me to come along tonight because they said the road was full of uncooperative crusties and protesters of all kinds littering the road.
"They said there was some risk that I would be egged."
Gosh - a risk of egging. How original. Yes the crusties are a nuisance but the real problem is how dull and unoriginal they are. Waving placards, chanting slogans, disrupting daily life, gluing themselves to this and that. It’s all been done before, the totalitarian politics, the anarchic evasion of responsibility, the designer scruffiness, the inability to build anything worthwhile – all of has been done before.
Why the blue blazes can’t they come up with something original? It’s all so dull, dull, dull. As if they watch the BBC news, read the Guardian, believe what Greta Doomberg says, think polar bears are going the way of the dodo, think totalitarian political nostrums might actually work because nobody ever tried them before. Strewth – they even seem to think they are radicals.
It’s been done before, over and over again. It’s tedious, uninteresting, useless, unproductive, dimwitted, intellectually dead, hopelessly naive but worst of all it’s dull.