BORIS Johnson has said he agrees with the aims of Extinction Rebellion but "deplores" their tactics - as the protests entered their third day.
The Prime Minister said the group are "right to rebel" against the damage being inflicted on Earth by climate change but accused the eco-warriors of causing more pollution with their disruption in the capital.
It marked a softer tone from the PM who had branded them "importunate nose-ringed climate change protesters" on Monday night.
Routes in and out of Westminster were completely blocked by protesters yesterday.
This morning more activists gathered on Whitehall and others continue to occupy the roads outside the Home Office.
Mr Johnson expressed sympathy with the aims of the group.
He told the Standard: "I deplore their tactics, but I basically think that they are right to rebel against the extinctions that are taking place.
"As far as they are disrupting traffic and causing people to sit idling in their cars, they’re obviously producing the opposite of what they claim to want.
"In so far as they are causing more pollution and more congestion, that’s not useful.”
By 9.30pm last night, the Met Police had arrested 261 people as part of yesterday's protests - bringing the total number of arrests from the first two days to 580.
One of those arrested today was a 91-year-old man.
Met officers have had leave and rest days cancelled and are working 12-hour shifts.
Meanwhile the National Police Chief Council said 500 officers will join Scotland Yard from all 43 forces.
The number of arrests marked a tougher stance from the police who had come under fire in April when they were filmed larking around with activists on Waterloo Bridge who had caused travel misery to ordinary Londoners.
But police were accused of "standing around the edges" and yesterday missed at least two opportunities to remove vehicles blocking Trafalgar Square.
Transport Secretary Grant Shapps said the Met should be taking "more robust action" against demonstrators who have effectively taken over the streets surrounding Parliament.
Rob Callender, 28, from Islington, spent Monday night locked on top of a trailer that had been driven into Trafalgar Square by a Land Rover Discovery.
He said that the police had passed up blankets to keep him warm.
Thousands of protesters ignored an order under section 14 of the Public Order Act to restrict their protest to the pedestrianised area of Trafalgar Square or face arrest, but by last night little attempt had been made to enforce it.
Tents remained in place on Trafalgar Square, beside Westminster Abbey and outside the Home Office.
Last night groups from Westminster Bridge and The Mall joined environmentalists at Trafalgar Square - where many were seen dancing during an impromptu rave.
Extinction Rebellion said it would disrupt London City airport tomorrow.
Organisers said they want to stage a "Hong Kong style" occupation of the terminal building by lying, sitting or gluing themselves in front of the gates.
They have told protesters to wear "business clothes" and buy a single one-way ticket that departs from the airport in order to get through security.
'A DISGRACE'
On the second day of action climate change activists glued themselves to the Department of Transport and to the underside of a lorry parked in the middle of the road outside the Home Office.
Environmentalists also set up a "village" under Nelson's Column with its own improvised cycle lane, food stalls and a "well-being sanctuary" for tired or stressed protesters.
Protesters took part in an interpretive dance session in Trafalgar Square where they were told: "This is how we make a difference...this is how we make a change".
Meanwhile, a group placed 800 potted trees outside Parliament, in Old Palace Yard, as they called on the government to plant billions of trees across the UK.
Extra police will arrive throughout today and tomorrow, as officers step up their operations to clear some streets, which are still blocked off for a third day.
On Wednesday mothers staged a mass breastfeeding near Parliament Square to "plead for the lives" of their children.
A man who lost both of his legs in the 7/7 terror attack blasted the protesters yesterday after he was unable to get to Westminster to attend a prestigious reception at the House of Lords on Tuesday night.
Dan Biddle, 40, told The Sun: "I am furious about it. I agree we have to deal with climate change, but this isn’t the way to get the message across.
"I think it's a disgrace the protesters have impacted this event like this — there doesn’t seem to be much respect there."
Dan, of Abergavenny, Monmouthshire, was due to attend the annual Shaw Trust Power 100 reception honouring the most influential disabled folk in Britain.
He said: "Everyone there has overcome adversity and being recognised for the work they do is a huge honour. Not being able to get there is a sickener."
Activists were also branded as hypocrites when a number of eco-warriors were seen popping into McDonald's, which boasts that it sells 75 hamburgers every second.
Tory MP Ben Bradley said: "The lack of self-awareness is absolutely staggering".
Broadcaster Piers Morgan slammed the group on Good Morning Britain, saying: "The hypocrisy that comes with these people...they went to McDonald's for lunch.
"They are shameless hypocrites going to the epicentre of mass-produced food".
Other protesters were snapped drinking out of plastic coffee cups on Tuesday.
Traders at Smithfield Market also expressed anger about cost to business from the protests.
The protesters set up vegetable stalls to "disrupt the idea that Smithfield must always be a place of death and environmental destruction".
James Burden said that missing one day of trade would cost the 31 meat companies "millions" of pounds collectively.
Meat and poultry wholesaler Adeel Jamil, 39, said his business wouldn't be able to carry on much longer if the protests continued.
Another trader said: "It's a joke. Vehicles can't get in to collect the meat and it means we can't serve as many of our customers. It will cost our business alone £10,000 in one night".
Angry Londoners blasted the protesters, with piles of rubbish bags stacked next to Trafalgar Square and lorries unable to collect activists' garbage.
A street cleaner told Sun Online: "We are seeing a lot more rubbish. The lorry can't get through.
"If it doesn't get moved its going to pile up. It will attract rats".
A local pub manager slammed the "chaos" which was hitting trade and said bar staff's wages may be cut.
The manager said: "We are getting no deliveries. We have to walk 15-20 minutes to pick it up.
"We can't get any food delivered. We are much quieter. It is disruptive to business. All our clients are tourists and we have none here.
"If we are not making money I can't pay people".
Meanwhile workers from a building site at Admiralty House were forced to carry steel by hand a quarter of a mile as protesters had blocked their lorry deliveries.
Lloyd Elwyn, 29, said: "It's a f*****g liberty. An absolute liberty.
"We wouldn't have had to carry that steel this morning. Bunch of idiots. We left at five this morning to get here."
MOST READ IN NEWS
Last week the Met warned that the protests were taking officers away from other vital roles in the capital including tackling knife crime and domestic violence.
More resources have been used policing climate change protest than focusing on terror, it was said.