Nicola Sturgeon and Theresa May have been involved in a war of words over pupils on climate change strike. 

The Scottish First Minister has backed youngsters who are skipping school to take part in climate change protests, describing their actions as a "cause for optimism in an often dark world".

However, Theresa May has slammed thousands of young people over their mass walk-out from school. 

READ MORE:  Youth Strike 4 Climate: Thousands of school pupils walk out in strike

UK Education Secretary Damian Hinds warned pupils they should not miss lessons to take part in the strikes with a Downing Street spokesperson saying: "Everybody wants young people to be engaged in the issues that affect them most so that we can build a brighter future for all of us.

"But it is important to emphasise that disruption increases teachers' workloads and wastes lesson time that teachers have carefully prepared for.

"That time is crucial for young people, precisely so that they can develop into the top scientists, engineers and advocates we need to help tackle this problem."

However, the Scottish First Minister saw the protests taking a stand on climate change in a more positive light. 

Ms Sturgeon took to Twitter to offer her support, saying: "It's a cause for optimism, in an often dark world, that young people are taking a stand on climate change."

While she said the Scottish Government was a "world leader" in acting against climate change, the urgency of the issue meant "it is right that we are all challenged to do more and that we hear the voice of the next generation".

Teenager Holly Gillibrand from Fort William is one of those taking part in the protest, saying it would be a "momentous day".

She tweeted: "Young people all around the UK are uniting together in solidarity to demand that our leaders treat the climate and ecological crisis as the crisis it is."

READ MORE: Climate Strike comes to Scotland: Children skip school to protest 

Scottish Green Party education spokesman Ross Greer urged education bosses to back pupils who are taking part in the protests rather than punish them.

He said: "I commend every young person in Scotland and across the world who is joining this growing movement and speaking out against this existential threat to their future."

He stressed the Curriculum for Excellence system in Scottish schools "is based on the idea that we support our young people to become responsible citizens".

Mr Greer added: "Every school student who takes action against the climate crisis on Friday is doing exactly that.

"They should know that they will not be punished for defending their own future.
"They have the Scottish Greens' support and I hope they will have the support of their teachers and education authorities."

Strikes are taking place in 60 towns and cities across the country in the face of "an alarming lack of Government leadership" on climate change, Youth Strike 4 Climate organisers say.

Mounted police were used to move protesters off the roads as they blocked traffic during a climate change demonstration.

As protesters in London took part in the UK-wide Youth Strike 4 Climate action, some took to the city's famous buses to demonstrate.

Others scaled traffic lights or statues in Parliament Square, or sat down in front of double-deckers, prompting the Metropolitan Police to intervene.

A number of protesters were led off in handcuffs after being removed from the road by police.

John Bynorth, Policy and Communications Officer at the charity Environmental Protection Scotland said: “To see the school pupils protesting outside the Scottish Parliament, in Glasgow’s George Square and elsewhere across Scotland was an inspirational example of how one individual - Greta Thunberg – and social media can be a force for good in young people’s lives.

“The protests gave voice to thousands of Scots school-children who feel they have been excluded from the climate change debate and provided urgent homework for politicians and policy-makers as they consider how to reduce global warming and lessen the impacts on our planet of climate change.

“Scotland is on the right track partly thanks to the end of coal production, but more needs to be done to reduce emissions from transport and the area of agriculture in particular."