During a visit to York Jeremy Corbyn accused Theresa May of “subservience” to US president Donald Trump.
On an election campaign visit to the Innovation Centre at York Science Park, the Labour leader criticised the Prime Minister for failing to join fellow European leaders in pledging to keep up the fight on climate change.
A decision by Mr Trump to pull the US out of the Paris Agreement – the world’s first comprehensive deal on tackling climate change – has drawn widespread international condemnation.
The leaders of France, Germany and Italy said the deal cannot be renegotiated. But Mrs May did not add her name to that statement.
She did express her “disappointment” at the decision in a phone call with the US president, and stressed the UK remains committed to the landmark 2015 agreement to curb greenhouse gas emissions.
Mr Corbyn told the gathering in York that Mr Trump’s move was “reckless and dangerous”
He said: “Given the chance to present a united front from our international partners she (Mrs May) has instead opted for silence and once again subservience to Donald Trump.
“It’s a dereliction of both her duty to this country and our duty to our planet.
“This is not the type of leadership Britain needs either to negotiate Brexit or stand up to defend our planet in an era of climate change.”
Speech on jobs
Earlier Mr Corbyn outlined his policies on industry and employment in a speech at the Innovation Centre.
He set out plans to create one million “high quality” jobs by investing £250 billion in industry.
“When Labour talks about job creation we mean decent jobs, jobs which pay a real living wage, which people can get by on, and which give people a sense of pride and purpose,” he said.
“Labour will invest to drive growth across the whole of Britain, creating wealth which is shared across our country, rather than concentrated in the hands of the few.”
Mr Corbyn spent the night at the Grand Hotel & Spa in the city, preparing for what might be the toughest day of campaigning yet.
Question Time tonight
Theresa May will not be far away. She is campaigning in South Yorkshire today, including a visit to Doncaster.
The two contenders for Downing Street will then shape up for their final TV showdown of the General Election campaign as they take questions from voters in a live grilling expected to be watched by millions.
The Conservative and Labour leaders will appear separately on the BBC1 Question Time special in York tonight, as the Prime Minister has refused to take part in televised debates with her rivals.
David Dimbleby will host the programme, broadcast from the Ron Cooke Hub at the university in front of a selected studio audience.
Preparations are well underway at the Heslington East campus.
The clash comes as Conservatives stepped up their assaults on Mr Corbyn amid opinion polls suggesting that their lead over Labour is shrinking with less than a week to go to the June 8 election.