Extinction Rebellion activists are continuing protests despite a London-wide ban by police.
The group says it will challenge the ban, saying it believes it is unlawful. Lawyers and politicians have also criticised the move.
Meanwhile climate change protesters targeted the Department for Transport and MI5 on Tuesday morning.
A government spokeswoman said protests “should not disrupt people’s day-to-day lives”.
Extinction Rebellion’s co-founder, Gail Bradbrook, was arrested after climbing on to the entrance of the Department for Transport on Tuesday morning. Police also cleared further protesters from outside the building.
Activists have also been arrested on Millbank outside MI5’s headquarters, where a small group had gathered. Two men briefly sat in the middle of the road before being moved by officers.
On Monday evening, the Metropolitan Police began clearing protesters from Trafalgar Square following the announcement of a ban on the protests.
Under Section 14 of the Public Order Act, the force had imposed conditions requiring activists to stop their protests in central London by 21:00 BST on 14 October or risk arrest.
The Metropolitan Police said that the ban was imposed after “continued breaches” of a condition limiting the demonstration to Trafalgar Square.
Speaking to the Victoria Derbyshire programme, Extinction Rebellion campaigner and former Met Police officer Paul Stephens said: “Police are being really sloppy with the law, and it won’t stand up in court.”
He added that “there will be a judicial review”.
Mayor of London Sadiq Khan has said he is “seeking further information” about the decision to impose the ban and why it was necessary.
“I believe the right to peaceful and lawful protest must always be upheld,” he said.
A spokeswoman for the government said the UK was “already taking world-leading action to combat climate change”.
The statement added: “While we share people’s concerns about global warming, and respect the right to peaceful protest, it should not disrupt people’s day-to-day lives.”
‘Overreach of powers’
Meanwhile, lawyers have questioned whether the ban by police was legal.
Anti-Brexit barrister Jo Maugham QC said the move was “a huge overreach” of police powers, while human rights lawyer Adam Wagner described it as “draconian and extremely heavy-handed”.
Mr Wagner added in a tweet: “We have a right to free speech under article 10 and to free assembly under article 11 of the (annex to the) Human Rights Act. These can only be interfered with if the interference is lawful and proportionate. I think the police may have gone too far here.”
Shadow home secretary Diane Abbott tweeted: “This ban is completely contrary to Britain’s long-held traditions of policing by consent, freedom of speech, and the right to protest.”
Allan Hogarth, of Amnesty International, issued a statement saying the ban was “an unlawful restriction on the rights to freedom of expression and peaceful assembly”.
A number of demonstrations have been staged across the capital by Extinction Rebellion, which is calling on the government to do more to tackle climate change.
The protests were due to last two weeks and have led to more than 1,400 arrests.
The Met said there had been 1,457 arrests by 08:45 BST on Tuesday, in connection with the nine days of Extinction Rebellion protests in London.
Last week, the Home Office confirmed to BBC News that it was reviewing police powers around protests in response to recent demonstrations.
What are the rules around protests?
Police have the powers to ban a protest under the Public Order Act 1986, if a senior officer has reasonable belief that it may cause “serious disruption to the life of the community”.
Police are also under a duty to balance the task of keeping the streets open with the right freedom of assembly under the Article 11 of the Human Rights Act 1998 and freedom of expression, under Article 10. These rights are not absolute – the state can curtail them.
However, the BBC’s home affairs correspondent Dominic Casciani said: “The test, if and when it gets to a court battle, is whether police action was proportionate to threat and only what was strictly necessary.”
By law, the organiser of a public march must tell the police certain information in writing six days in advance.
Police have the power to limit or change the route of the march or set other conditions.
A Section 14 notice issued under the Public Order Act allows police to impose conditions on a static protest and individuals who fail to comply with these can be arrested.
Downward dogs and yoga mats have replaced cars and buses on London’s Tower Bridge as part of Car Free Day.
The mass yoga session was one of a number of activities taking place in the capital as more than 16 miles (27 km) of streets were shut.
Bank junction was turned into a festival space while children will race go-karts in the Square Mile.
The closures will be in place until 19:00 BST with roads elsewhere expected to be busy as a result.
Tower and London Bridge were shut at 07:00 BST along with streets in parts of the City, Southwark and Tower Hamlets.
Among the other activities taking place were a hedge maze in Cheapside and classic cycle rides on Tower Bridge.
Organisers hope more than 150,000 people will join the event, which has been named Reimagine.
Away from the centre, 15 boroughs will be running their own Car Free Day celebrations and more than 340 “play streets” – safe spaces for local people to socialise and play – have been approved by 24 boroughs.
London’s Mayor Sadiq Khan said the day was about “demonstrating our commitment to cleaning up our toxic air and experiencing a greener way of living”.
Transport for London has warned that those who do take to the roads should expect “significant delays”.
A social media blackout, a “crazy amount of belief” and a “table that does not lie” – welcome to the closest Super League relegation fight ever.
Four clubs, equal on points with one game to go, are all at risk of the drop.
One coach has simply labelled “the ramifications” of the do-or-die night on Friday the 13th as “destructive”.
BBC Sport looks at how Wakefield and London, two sides that face each other in a relegation showdown, as well as Huddersfield and Hull KR are dealing with the biggest week of their season.
How they line up on ‘fright night’
‘No need to ram message down players’ throats’
A social media blackout has been imposed on Wakefield’s players as head coach Chris Chester tries to get them to focus on the game and not its consequences.
“The players know enormity of what is at stake on Friday night,” he told BBC Radio Leeds.
“The social media blackout is to take pressure away from them and have them solely focused on getting a result.
“It (relegation) has not been discussed. They don’t need me ramming it down their throats.
“The one thing the guys will be on Friday is ready.”
A boost for Wakefield, who have struggled for long periods with an injury-hit squad, is that 33-year-old England centre Ryan Atkins is due to make his long-awaited return.
Atkins, who started his career with Trinity in 2006 before going on to spent a decade at Warrington, was to complete his more next season but Trinity brought his switch forward.
“He’s been a real positive influence on the group for the last three or four weeks since he’s been here,” Chester said. “He’s played in all the big games and knows what to say.”
What it will take to stay up? Wakefield’s home game against London Broncos has been billed as a relegation showdown, and victory certainly means Wakefield stay in Super League. If London beat Wakefield for the third time this season, then Trinity would go down if both Huddersfield or Hull KR win.
So, how do Wakefield find themselves facing the drop?
BBC rugby league reporter Matt Newsum
“Injuries have been the crux of Wakefield’s struggles against the drop, robbing Chester’s side of several major performers like prolific winger Tom Johnstone for pretty much the whole season, prop David Fifita for large chunks and as well as influential back-rower Tinirau Arona at a key time.
“Injuries have not helped their loss of form, with an alarming late-season slump remaining a concern for Chester – who at least acquired smart loan signings such as Morgan Escare for the run-in.”
‘An absolute write-off of a season’
England winger Jermaine McGillvary said the players take responsibility for the relegation trouble Huddersfield Giants finds themselves in.
The winger said they “need to stand up and be counted” when they host Catalans Dragons, a side they have failed to beat in their last three meetings.
“The table doesn’t lie, we deserve to be where we are,” McGillvary said.
“I’m not sulking because I think we deserve to be higher, we have been shocking all year. The season has been an absolute write-off regardless of what happens.
“Everyone is hurting, not just the players but staff, fans and everyone involved. It’s all our, the playing staff’s, fault.”
The “positive”, the long-serving Giants winger added, is that they remain in control of their destiny.
“There are three other teams in the situation as well and it is still in our own hands,” he said.
“If we get a win against Catalans we stay up. It is all down to us.”
What it will take to stay up? A win at home against Catalans Dragons, a side who have nothing to play for, assures survival. Defeats for London or Hull KR will also mean they are safe – even if they fail to triumph themselves.
What’s been behind Huddersfield’s woes, leaving them third from bottom and in real danger of relegation after 28 games?
BBC rugby league reporter Matt Newsum
“Huddersfield lost key playmaker Danny Brough last winter – coincidentally to Wakefield – and their chopping and changing in the halves since has not helped their attacking rhythm.
“They have one of the best wingers in the competition in McGillvary, who has again stood up with 16 tries, but it is defensively where Giants have struggled – conceding second most points in the league. Injuries have also hampered the Giants, limiting the outings for powerful forwards such as Joe Wardle and Seb Ikahihifo.”
‘Relegation causes destruction’
Hull KR boss Tony Smith has refused to let his players get paralysed by fear as they try secure the club’s Super League status with a trip to play-off-bound Salford Red Devils.
A late Jay Pitts try for London in their 20-16 win against Rovers a week earlier set up the final-night drama for the four clubs, when a Broncos defeat would have relegated them and spared Smith’s men as well as Huddersfield and Wakefield.
“We understand the ramifications of this week, as we understood the ramifications of last week,” he told BBC Radio Humberside.
“It is not being taken lightly but we are not going to sit around an worry about things when we have to take them into our own hands.
“The best way to do things is in a positive manner, with a smile on your face and looking forward to the challenge rather than feel like the pressure is getting to us.”
Smith, who suffered relegation in his first season as coach in Britain with Huddersfield in 2001, said the drop would “cause destruction”.
“It can hurt, and hurt clubs for many years,” he said.
“We are determined to get things great here over the next few years and we will regardless of which competition, but we certainly want to be in Super League and have that as our starting position.”
What it will take to stay up? Stopping Salford’s seven-game winning run is a good place to start. If they upset the form guide in Greater Manchester they survive. But they could still lose and stay up, even if bottom club London Broncos win. That would involve Huddersfield losing at home to Catalans by 13 points more.
But why, with one of Super League’s leading coaches, are Hull KR dicing with relegation?
BBC rugby league reporter Matt Newsum
“Hull Kingston Rovers gambled on sacking veteran super coach Tim Sheens and bringing in Tony Smith, who has eked out some impressive results since arriving. Inconsistency, however, has plagued them.
“A bit like their city neighbours, you never know what to expect. Danny McGuire’s brains and guile work when the pack is firing, and the Robins are certainly capable if scoring points but as recent defeats from winning positions by relegation rivals Huddersfield and London show, they can struggle to finish teams off – and that lack of ruthlessness has cost them.”
Broncos ‘know’ they can survive
Half-back Brock Lamb flew in to London to aide in their salvation – the former Newcastle Knights and Sydney Roosters play-maker just wishes he could have made it to the UK capital sooner.
The 22-year-old says the Broncos, the club with Super League’s smallest budget which has tried to stay in the top flight by keeping the promotion-winning side together, have quickly become “family”.
Resilience has been the hallmark of their campaign, and the 20-16 win over Hull KR to set up the desperate relegation situation on Friday night is the finest example of how they have defied the odds this season.
“The belief in the side at the moment is crazy,” Lamb told BBC Radio London. “It is a good squad and we just want to win.
“It is the last time this team will ever play together. We have people leaving and some staying. We want to send them out with a bang and hopefully stay up to do it for the club and the fans.
“I wish I had come here earlier so I could have experienced it from the start. It has been awesome in the last six weeks because everybody just believes. We have had a few poor games but the next training day everyone is ready to rip in again. Everyone knows we can do it.”
What it will take to stay up? Beating relegation rivals Wakefield in West Yorkshire is realistically the only thing that will keep London Broncos from making an immediate return to the Championship.
They were tipped to be easy pickings in Super League this season, but will London really escape relegation?
BBC rugby league reporter Matt Newsum
“London Broncos were barely expected to win a game this season let alone be in with a shout of survival. While they have shipped plenty of points, they have remained pretty competitive.
“They are not the biggest, or strongest, but they have won games and hurt teams by out-enthusing opponents, smothering them with aggressive line speed and then hitting them with quick breaks from a pacy back-line.
“Their fans have stuck with them, there is some pride in how their ‘behind-the-eight-ball’ side has got accustomed to Super League given their unexpected promotion.
“Unlike their fellow strugglers, they will not be dreading the end-of-season review, whatever happens. They have also recruited smartly for an end-of-season boost, as ex-Newcastle Knights and Sydney Roosters half-back Brock Lamb has already formed a smart understanding with lock Luke Yates – his former Knights team-mate.”
Passengers are facing travel disruption after an entire London Underground line was suspended due to a signal systems failure at the main control centre.
One commuter tweeted that he “hated the Northern Line”, which was suspended just before 06:00 BST.
The Tube line connects transport hubs Waterloo, King’s Cross and Euston and is used by more than 800,000 people every day.
Most of the service had reopened by 11:00, Transport for London said.
Commuter Mario Toubes-Rodrigo said he missed his pre-booked train to Milton Keynes because it took 75 minutes to make a journey that normally takes 20 minutes.
“I waste so much time and money on the Northern line,” the microbiologist said.
“I get up to leave my house even earlier and pre-book my train tickets to avoid problems but I still end up having to buy on the day tickets and turning up late to work.”
There is still no service on the Northern Line between Camden Town and Kennington via Charing Cross.
Tube tickets are being accepted on Southeastern and Thameslink trains, as well as on trams and buses.
Both the Bakerloo and Metropolitan lines also have minor delays as a result of the signals failure.
Replacement buses through London were reported to be overcrowded, with one commuter complaining it was “everyone for themselves”.
The delays come as schools open for the new term this week and commuters on social media complained of having to queue to access stations.
People also said they had been forced to miss trains from King’s Cross and Euston because of the disruption.
Brian Woodhead, London Underground’s director of customer service, said: “I am extremely sorry for the disruption suffered by customers on the Northern Line today following a signalling system failure at our control centre.
“Our engineers are working hard to fix the problem and restore a full service as quickly as possible.”