THERESA May has been "empty-chaired" by organisers of a politicians' round-table with the Swedish teenager behind a global wave of youth climate change protests.

Sixteen-year-old Greta Thunberg met Westminster party leaders, including Labour leader Jeremy Corbyn and the SNP’s Westminster leader Ian Blackford, as Extinction Rebellion protesters gathered outside in Parliament Square.

Holly Gillibrand, a pupil at Lochaber high school in Fort William who has been taking strike action every Friday demanding more action on climate change, was also present at the round-table and expressed disappointment at Mrs May’s non-attendance.

“It’s very disappointing she didn’t come because she’s the Prime Minister of the UK and she is the one in charge; she should be listening to us and engaging with us but she’s not,” declared 13-year-old Holly.

Organisers of the meeting pointedly left a place at the table for Mrs May, who was chairing the Cabinet in Downing Street at the time.

They said no response had been received to an invitation issued to the PM. Earlier, Mrs May’s spokesman said he was "not aware" of any request for her to meet Ms Thunberg.

The teenager won worldwide fame after beginning a solitary school strike for the climate protest outside the Swedish Parliament in August last year.

Her stand inspired school walkouts around the world with hundreds of thousands of young people in countries, including the UK, joining the Global Climate Strike in March.

Along with Mr Corbyn and Mr Blackford, Ms Thunberg also met Sir Vince Cable, the Liberal Democrat leader, Green MP Caroline Lucas and Liz Saville Roberts, Plaid Cymru’s Westminster leader.

Opening the round-table talks, the 16-year-old activist - who earlier met Commons Speaker John Bercow - told the MPs: "We just want people to listen to the science."

Later in a packed room in the Commons, she said her future and those of her fellow children had been "sold".

Ms Thunberg said: "We probably don't even have a future anymore. That future has been sold so that a small number of people can make unimaginable amounts of money. It was stolen from us every time you said 'the sky is the limit.'"

Ms Lucas told Ms Thunberg: "I hope this will be the beginning of an ongoing dialogue with young people. All of us are really committed to trying to ensure that there's an ongoing way to really make sure that all of our policies and all of our work in Parliament is properly scrutinised by young people with a perspective on climate in particular.

"We want young people's voices to be heard in Parliament. This is such an important moment, when the Inter-Governmental Panel on Climate Change say we have just 11 years left to get off the collision course we are on for climate catastrophe.

"That sense of urgency is here as never before at a time when there have been protests on the streets not just of London but around the country and all the different nations of the UK. More than ever, politicians have our ears open to your message."

Mr Corbyn told Miss Thunberg: "Well done for what you have done."

The Labour leader tweeted an image of himself and the climate change activist in front of a portrait of the late parliamentarian Tony Benn.

He wrote: "It was a pleasure welcoming UK youth climate strikers and @GretaThunberg to parliament. Young people will be the most affected by climate change - seeing them take charge of their future is inspiring. Labour's committed to working with young people campaigning to save our planet."

Michael Gove, the Environment Secretary, told Ms Thunberg she had been heard and admitted "we have not done nearly enough".

Speaking at the climate change event, he added: "Suddenly in the past few years it has become inescapable that we have to act.

"The time to act is now; the challenge could not be clearer. Greta you have been heard."

Mr Blackford stressed how it was important for politicians to engage with young people and “show the leadership that was necessary to make sure that we do have a planet that we are able to pass on to future generations”.

The Highland MP spoke of a “sense of responsibility for future generations” and highly commended the campaign that Holly had embarked upon.

Asked what the reaction to her activism had been from fellow pupils and her teachers in Scotland, Holly said: “From pupils, they are not quite sure how to approach it because I doubt they have seen much activism in their lifetime. We don’t get good education about climate change; they don’t really understand why we are doing it. My teachers are quite supportive of me but my head teacher doesn’t like what I’m doing.”

She added: “All the politicians are quite supportive of the strikes but we’re not doing it even nearly enough because the Paris Agreement says we need to be at zero global emissions by 2050 and the UK’s current targets are way too low.”