Jeremy Corbyn has heaped praise on schoolchildren and college students who skipped lessons and lectures to join the largest worldwide climate protest in history as eco-activists took over London today.
Activists, many of whom carried Extinction Rebellion flags and banners, descended on the capital as the Global Strike 4 Climate Change movement kicked off in the UK to coincide with protests all over the planet.
The Metropolitan Police said two people had been arrested in the Strand for breaching conditions imposed on the protesters which dictate they must gather in a specific place in Westminster, central London.
Schoolchildren, many of them dressed in their uniforms, joined in on more than 200 different climate events in Britain after they were urged to walk out of classes throughout Friday.
Politicians have been split on whether or not pupils should be skipping lessons to attend the climate protests, with Labour leader Jeremy Corbyn and mayor Sadiq Khan among those to commend young demonstrators.
The Labour leader was greeted by huge cheers and cries of 'oh, Jeremy Corbyn' as he addressed thousands of demonstrators near the Houses of Parliament.
He commended the younger members of the audience for not arriving at school this morning, telling them: 'Thank you for being here to teach me and everyone else a lesson about the environment.'
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In a speech outside the Houses of Parliament today, Jeremy Corbyn heaped praise on schoolchildren and college students who skipped lessons and lectures to join the largest worldwide climate protest in history as eco-activists took over London
Schoolchildren protest with banners outside parliament in London after youngsters were urged to skip lessons in order to take part in demonstrations
The Labour leader was greeted by huge cheers and cries of 'oh, Jeremy Corbyn' as he addressed thousands of demonstrators near the Houses of Parliament
Mr Corbyn commended the younger members of the audience for not arriving at school this morning, telling them: 'Thank you for being here to teach me and everyone else a lesson about the environment'
Youngsters take part in today's climate change demonstrations after thousands skipped lessons and lectures this morning
A protester is arrested by police officers stationed outside outside King's College London as mass demonstrations hit the UK this morning
A protester is led away by police in handcuffs this morning (shown left), while an Extinction Rebellion activist is shown waving a XR flag outside King's College London
Two protesters are placed in handcuffs outside King's College London near the Strand as mass demonstrations kicked off in the capital today
Mr Corbyn said: 'Thank you to each and every one of you who is here today showing our determination to combat climate control, protect our environment and our planet.
'And to those who say school students shouldn’t be in school today I say thank you for being here to teach me and everyone else a lesson about the environment.
'The reality is this planet is destroying itself. In the last 50 years, 60 per cent of animals have been rendered extinct by global warming, climate change and grotesque levels of exploitation of natural places.
'Why is it that children growing up alongside a major road her in London or wherever should breathe worse air than better off children in a leafy suburb?'
'We want every country on-board with this, fully signed up to Paris Climate Change Accord, and going a lot further than that.
So I say to people all over the world today that are demonstrating against climate control and its support for the demand of a climate emergency, well done to all of you.
'It feels like those global demos we held in 2003 to try and stop that terrible war in Iraq. People coming together across the planet for peace, for justice and for sustaining our world and our planet.'
State school leaders had urged youngsters not to take part, saying they understand the strength of feeling around the issue, but have concerns about pupil welfare.
But Suzie Longstaff, headmistress of the £18,900-a-year private Putney High School in south-west London, said that young people should be able to make their own decisions about whether to take part in today's action.
Thousands of protesters gather near the Houses of Parliament for today's climate change demonstration, where Labour leader Jeremy Corbyn spoke later this afternoon
Police officers carry a protester away in the Strand after issuing section 14 notices amid mass-scale demonstrations in London today
An aerial shot from Central London shows thousands of protesters gathering during one of more 200 events across the UK this afternoon
Scottish comedian Billy Connolly was among those to lend his support to protesters marching in Glasgow this afternoon
Labour leader Jeremy Corbyn tweeted an image from the protest in London and is due to address a rally of climate strikers outside Parliament, while dozens of other mass-scale events are being held up and down the country
Students carrying Extinction Rebellion banners and flags are shown marching through the streets outsude the Houses of Parliament
Police officers form a cordon outside Parliament Square, as demonstrators were asked to protest in specified areas
A young child looks out at the masses of people who gathered in central London today for the what is expected to be the world's largest ever join climate change demonstration
Rolling Stones singer Mick Jagger was among those to give their support to those taking part in the Global Climate Strike
The Global Strike For Climate in London is being held only days ahead of the scheduled United Nations Climate Change Summit in New York
Hundreds of protesters hold a 'die-in' at the UK Student Climate Network's Global Climate Strike in Cambridge this afternoon
But Ms Longstaff said: 'Every day we are educating the young people of the future to speak out and make their own decisions.
'We are trying to provide a modern and relevant education which includes connecting to topics that they feel passionate about. We can't pick and choose what those are.
'I'm proud that Putney students have both a social and environmental conscience and I applaud them. Those who feel strongly about protesting will be there.'
Sylvie Craig, 11, and her friend Eva De Pear, 12, both of Shepherds Bush in west London, took the day off school and brought their mothers to the demonstration.
Sylvie said: 'Climate change is really important. We can't just talk about it, we have to do something about it '
Her mother Bay Garnett, a fashion director, said: 'I am here for my children and all children. I think every mother feels the same. They need a healthy planet to live on.'
Eva skipped her biology lesson on Friday, saying that going to it made 'no sense' because 'the planet is in real big trouble'. She said: 'I am here to teach people a lesson instead of learning a lesson.'
Her mother Leila Amanpour said: 'I feel that unless we come out into the streets, especially the children, the Government is not going to do anything about climate change.'
Protesters gather ahead of the UK Student Climate Network's Global Climate Strike at Millbank in London today
Young climate strikers across the country (pictured here in Millbank, London this morning) are taking to the streets as part of a global protest to demand urgent action to tackle climate change
Protesters hold banners as they attend the Global Climate Strike taking place outside the Houses of Parliament this morning
A sign posted on the outside of the Ben and Jerry's store in Wardour Street, London, shows the firm's support of the climate strikes today
Thousands of protesters, including hundreds of children, many wearing school uniform, gathered in Birmingham's Victoria Square before marching through nearby streets.
Meanwhile, West Mercia Police advised drivers to find alternatives routes after around 40 Extinction Rebellion members intermittently blocked traffic in Worcester.
Tweeting a photo from a climate strike in London, Mr Corbyn said: 'Young people here and across the world are making it impossible to ignore the environment and climate emergency.
'This is the wonderful youth Climate Strike in my constituency; now I'm on my way to the main London demonstration.'
Liberal Democrat leader Jo Swinson tweeted: 'Great to see so many people the Glasgow Youth Climate March, all raising awareness of the climate crisis.
'We demand immediate, strong action to stop irreversible damage. We must protect both our planet and future generations.'
Workers joined thousands of schoolchildren in taking part in the mass-scale demonstrations in London today (pictured in Westminster)
Medical professionals were shown marching near Westminster holding up banners and homemade signs declaring their support of climate intervention
State school leaders have urged youngsters not to take part, saying they understand the strength of feeling around the issue, but have concerns about pupil welfare
Students hold placards as they attend a climate change demonstration in London this morning (pictured on the lawns outside the Houses of Parliament)
London Mayor Mr Khan called on the Government to 'step up' action on climate change, adding: 'I am standing in solidarity with all those who are taking part in the Global Climate Strike.
'Here in London, City Hall staff have also been encouraged to observe the strike by taking time out of their day to send a message to the world that London demands more ambitious climate actions from governments.'
However business, energy and clean growth minister Kwasi Kwarteng said he could not endorse children leaving school to take part in the protests, which have been inspired by teenage eco-activist Greta Thunberg.
He told BBC Breakfast on Friday that he supports the 'energy and creativity' of students, but said time spent in school is 'incredibly important'.
Jessica Ahmed, 16, who is studying for an International Baccalaureate had emailed her school to warn that she would be walking out on Friday.
Speaking at a protest in Westminster, Miss Ahmed of Barnet, north London, said: 'There are no excuses in this. School is important but so is my future.
'If politicians were taking the appropriate action we need and had been taking this action a long time ago when it was recognised the world was changing in a negative way, then I would not have to be skipping school.
'I would be doing the maths exam I have studied for.
She called on the