The revolution begins in ­London on Saturday night. Ideally it will be peaceful, but if G20 demonstrators meet police aggression, they will respond with violence. This prediction comes from anarchist, Chris Knight, a 66-year-old professor of anthropology at the ­University of East London, whose group is at the heart of a series of high-profile actions planned to start across the capital this weekend.

Knight, whose house in a south ­London street known as Millionaires' Row serves as the unlikely headquarters for the G20 Meltdown group organising the siege of the Bank of England on 1 April, intends to “harness the rage” of social action groups and wants to use “Earth Hour”, a worldwide “power down” planned by the World Wildlife Fund to express solidarity against ­climate change, to target City firms that fail to turn off their lights at the appointed time of 8.30pm on Saturday night.

“We are expecting up to one million people on the streets of the capital on Saturday afternoon and just before sunset thousands of us will fan out across the City to enforce Earth Hour,” he says. “We're focusing on Canary Wharf but every office block in London with lights on will be fair game. We will go to the building and demand they switch off the lights. If they refuse, our agents will find ways to enter the building, even if it means knocking down doors and ­windows to break in.”

Is he advocating violence? “Not against people but I'm not too bothered about damage to property,” he says brazenly. “Let's just say we prefer to avoid it and expect to be invited in by cleaners and janitors. But make no mistake, we're prepared to go the whole way. One way or another, those lights will get switched off.”

Knight “strongly suggests bankers should stay away from the City next week. If you're thinking of coming in, my advice is don't'. People are incandescent about your bonuses and the way you've destroyed their lives. We plan to lay siege to the financiers who have brought us into this recession and who continue to pursue policies that are destroying our planet”.

As for the police, “if they want ­violence, they'll get it”, adds Knight, a former member of Labour's extreme Left-wing Militant Tendency who now calls himself a revolutionary communist. “We intend to be peaceful but if they press their nuclear button, I'll press mine. It's called mutually assured destruction'. If Gordon Brown deploys his riot police, or sends in his agents provocateurs to start trouble as an excuse to attack us, all hell will break loose.”

Knight's incendiary rhetoric may be nothing more than bluster but the authorities are taking it seriously. The Metropolitan police have mobilised more than 2,500 officers and cancelled all leave in an operation expected to cost £7.2 million. The head of security at Canary Wharf yesterday called Knight on his mobile phone in an attempt to prevent the area around One Canada Square turning into a battle ground.

There is no doubt that the G20 Summit, which sees the arrival of the leaders of the world's major economies to tackle the credit crunch as well as the first visit to London by President Barack Obama, is a boon to hardcore protesters and ­rabble-rousers seeking to orchestrate a Seattle-style week of protests. Until now, few had heard of Professor Knight and his coterie: Camilla Power, an anthropology lecturer at the University of East London, and Marina Pepper, 41, a former Playboy “playmate of the month” who has taken up placards reading “Eat the Bankers”.

They met through Knight's Radical Anthropology Group (RAG), which explores the origins of society from a Marxist standpoint and pays homage to hunter-gatherer groups such as the Bushmen whose societies are “communist and egalitarian”.

Knight, educated at the Skinners' School in Tunbridge Wells and University College London, says they relaunched themselves last October as an anti-banker group called “The Government of the Dead”, the name inspired, he says, “by the hunter-gatherer belief that our ancestral spirits should rule us rather than our obsession with money”. Since then, they have been busy. Knight's garden is awash with home-made props, including bloody effigies of dead bankers to be hung from lamp-posts when protesters converge on “the belly of the beast”, the Bank of England, on 1 April.

Such props make a strange sight among the flowering magnolias, especially on this wide suburban road in ­Lewisham where houses go for up to £1.3 million.

My interview with the professor, a father of three who eschews marriage, takes place in his cluttered spare bedroom. He sprawls on a futon on the floor, dressed in old corduroy trousers and socks and tells me he earns £35,000 a year as a lecturer but is not interested in money. “I don't own this house, I rent it for £1,000 a month. In fact, I've never owned anything. I've got a battered old banger, a 15-year-old Ford Mondeo that's worth about 20 quid, and that's it.”

When I ask about his 48-inch widescreen television in the living room that doubles as the headquarters of G20 Meltdown, his assistant, Camilla Power, quips: “It's because the revolution will be televised — yeah, in digital high-definition.”

Knight himself vacillates between a dry sense of humour and a spiky anger that explodes intermittently, especially at mention of “New Labour”.

Back in 1981, he says, he and two others set up in his kitchen the Labour Briefing group that orchestrated Ken Livingstone's coup to take control of the GLC and wrest power from the conventional Labour leaders. “Now we face a similarly critical moment,” he says. “The G20 Summit will be a fiasco for Gordon Brown. We're on the brink of a Velvet Revolution that will be triggered by the collapse of the banks.”

Indeed, as Knight keeps reminding me, “the revolution begins on Saturday”, organised from his living room and spread by lurid anti-banker pamphlets, word of mouth and Facebook groups.

He's vague on details but says: “If we succeed with our revolution in the capital in the next week, that will immediately spread to Strasbourg where our anti-globalisation colleagues in France and Germany will stop the Nato summit scheduled for 4 April. Our revolution will spread out across Europe so that, come June, my prediction is that planet earth will be one country. There will be no borders. What we are about to witness is the world turned on its head.”

In Knight's parallel universe, he will become general secretary of the Labour Party, while John McDonnell, Labour MP for Hayes and Harlington, replaces Mr Brown as leader. When I ask if he has informed McDonnell of his plans, he says: “John is a friend of mine, has been for years. He's a socialist, as I am, but increasingly he's moving towards direct action. He's talking at the Alternative G20 Summit we're holding at my campus on 1 April and together we'll be looking forward with glee to the collapse of the financial system.”

Knight expects the coming week to be like a massive exciting general strike. “A bit like Seattle in 1999 although not quite as big or international as we haven't had as long to organise it.

“The whole thing will be spectacular. There are plans afoot, not organised directly by us, to dump tons of sand outside Downing Street and turn areas of the City into giant sandpits. There could also be a rebel raft regatta, using inflatable dinghies and rafts to access the City via the Thames. So many groups are involved. It's the biggest coalition ever.”

On his living room wall is a rudimentary chart in black ink, the blueprint for the action on 1 April. It shows four arrows converging on the Bank of England. It seems unreal that something so crude and half-baked can cause the police, and Londoners, a £7.2 million headache — and that's assuming it all passes off peacefully.

WHO IS PROFESSOR CHRIS KNIGHT?

CHRIS Knight was the eldest of five children of a father who gave up his career as a school teacher to follow his romantic ideal and become a self-sufficient farmer in Somerset and then Devon.

The farms failed and the family frequently moved around, so much so that Chris attended 13 primary schools and three grammar schools. He did A-levels in maths, physics and chemistry but decided to pursue an arts degree, with the only option being Russian literature at Sussex University in 1961.

Barred from spending his third year in Moscow because of the Cold War, he went to Paris and lived with "Russian emigrés". He completed a masters degree, became interested in anthropology and more involved in "revolutionary politics".

As a student he spent a week in Norwich Prison for occupying an American airbase and worked as a Post Office van driver and a teacher at a south London comprehensive.

By the early 1970s he was a member of the Revolutionary Community Party and claims he organised a picket of an electricity sub-station in Neasden in the 1980s in solidarity with striking miners.

Later involved in the "reclaim the streets movement", he backed striking Liverpool dockers in the 1990s and the first large anti-capitalist protests in the City in 1998.

• 

  All I want to know is... how big is my bonus?

  Cityboy is the banker who made his name by telling all about his wild times in high finance. Now as bonus season approaches, he says the City is filled with fear - and greed

  ---

• 

  No sex in New Moon please, we're vampires

  Film review: The creepiest thing about the second adaptation of Stephenie Meyer's Twilight books - New Moon - is its obsession with teenage celibacy

  ---

Steamy scenes for Purnell in Turkish bath

Scheming over the future of the Labour Party continues even in the most unlikely places

All stories