Scores of climate protesters have gathered outside Parliament and vowed to put pressure on politicians returning to work after the Easter recess.

Extinction Rebellion (XR) members assembled in Parliament Square on Tuesday at around noon as influential 16-year-old activist Greta Thunberg was meeting party leaders including Jeremy Corbyn and Caroline Lucas in the Commons just yards away.

Campaigners are urging the Government to declare a climate emergency as protests enter a second week.

Activist Jay Monk, 49, said the demo was a signal of a “renewed push” to have politicians answer the group’s demands.

Dozens of police officers lined the fringes of the demonstration – with Scotland Yard earlier saying it had a “robust” policing plan in place.

The force has warned demonstrators they must leave a designated area by 11.59pm or be liable to arrest.

More than 1,000 people have been arrested during XR protests which started on April 15, while more than 10,000 police officers have been deployed.

The action has seen Waterloo Bridge and Oxford Circus blocked and a “die in” at the Natural History Museum.

Elsewhere, activists have glued themselves to trains, and some could even be seen perching in hammocks up trees overlooking Parliament Square on Tuesday.

Greta Thunberg
Swedish climate activist Greta Thunberg meets leaders of the UK political parties at the House of Commons in Westminster (Stefan Rousseau/PA)

Swedish schoolgirl Miss Thunberg, who has inspired international youth climate strikes, previously told an XR protest in London that humanity faces an “existential crisis”.

The Nobel Peace Prize nominee, who has Asperger’s, is also expected to make a speech at a meeting in Portcullis House at around 2pm.

Theresa May was “empty chaired” at her round-table discussion in the House of Commons.

Miss Thunberg met Labour leader Jeremy Corbyn, Liberal Democrat Sir Vince Cable, Green MP Caroline Lucas and the Westminster leaders of the Scottish National Party and Plaid Cymru, Ian Blackford and Liz Saville Roberts.

Extinction Rebellion protests
A seat was left empty for Mrs May (Stefan Rousseau/PA)

A place at the table was left free for Mrs May, with a sign bearing her name, but she did not attend. The Prime Minister was instead chairing Cabinet in 10 Downing Street.

Student Jade Edwards, from Worcestershire, said: “If they listen to her that’s a great step forward for the planet and everything that lives in it.”

Philip McMaster, bearded and wearing red robes as part of a character he calls “Sustaina Claus”, called on politicians to engage with XR.

The Canadian former teacher said: “We have given authority to them. That is why they are in power.

“Now they need to act for the best interests of our children.”

Members of XR have previously indicated temporarily ending disruptive tactics to focus on political negotiations.

Protester Steve Jones, 53, suggested some of the disruption may be relaxed if the group was granted “meaningful discussions” with the Government.

Extinction Rebellion protesters at Parliament Square
Extinction Rebellion protesters at Parliament Square (Kirsty O’Connor/PA)

The Metropolitan Police said 1,065 people had been arrested in connection with the demonstrations by 10am on Tuesday, while 71 of those had been charged.

Three people have been charged by British Transport Police in connection with the protests.

A Scotland Yard spokesman said: “This number of arrests is unprecedented, and is diverting officers from their vital duty of tackling crime and keeping London safe.

“But they will continue to arrest those who occupy illegal protest sites and refuse to stop causing widespread disruption to the communities of London.”

Extinction Rebellion protests
Extinction Rebellion protesters lying down inside the Natural History Museum (Laura Parnaby/PA)

Meanwhile, several people accused of public order offences linked to the protests are due to appear at Westminster Magistrates’ Court.

On Easter Monday, at least 100 protesters laid down under the blue whale skeleton at the Natural History Museum in a stunt organisers called a “die in”.

Some protesters, wearing red face paint, veils and robes, remained to give a performance to classical music on the steps beneath the skeleton.