Sir Keir Starmer has urged the government to invest urgently in jobs that benefit the environment.
The Labour leader wants £30bn spent to support up to 400,000 “green” jobs in manufacturing and low-carbon industries.
The government says it will create thousands of green jobs as part of its overall climate strategy.
But official statistics show no measurable increase in environment-based jobs in recent years.
Speaking to the BBC as he begins a two-day visit to Scotland, Sir Keir blamed this on a “chasm between soundbites and action”.
He and PM Boris Johnson are both in Scotland this week, showcasing their green credentials ahead of November’s COP 26 climate summit in Glasgow.
Criticising the government’s green jobs record, Sir Keir points to its decision to scrap support for solar power and onshore wind energy, and a scheme to help householders in England insulate their homes.
He said: “It’s the government’s failure to match its rhetoric with reality that’s led to this, They have used soundbites with no substance.
“They have quietly been unpicking and dropping critical commitments when it comes to the climate crisis and the future economy.
“It’s particularly concerning when it comes to COP 26.
“Leading by example is needed, but just when we need leadership from the prime minister on the global stage, here in the UK we have a prime minister who, frankly, is missing in action.”
Writing for the Guardian, he said the UK should follow the example of US President Joe Biden, who has put jobs at the centre of his climate change policy.
The Labour leader added that the UK government’s response to the climate threat had been “small,” adding it was “implausible” the UK was on track to meet its emissions targets.
A government spokeswoman said ministers would follow the advice of their expert panel, the Green Jobs Taskforce, on how to seize the economic opportunities presented by the shift to a climate-friendly economy.
She said the taskforce’s recommendations – published last month – were “a big step forward in delivering the skilled workers and green jobs essential for the UK’s transition to net zero”.
Several initiatives were already underway, including green apprenticeships for nuclear engineers and wind turbine operations, green skills “bootcamps” delivering free training for adults, and a scheme to boost skills in electrification technologies, she added.
Climate summit pressure
Mr Johnson is under increasing pressure over his plans for combating climate change.
International negotiations preparing for the COP conference are proving tortuous, and the PM’s being criticised by some Conservative backbench MPs who argue that the cost of achieving near-zero emissions by 2050 is too high.
The Office for Budget Responsibility (OBR) has suggested that abolishing the UK’s emissions would add 21% of GDP to the national debt by 2050 – but those costs could climb twice as high if the government delays action.
It found that early action to decarbonise the economy would have a smaller net impact on the UK’s finances than Covid or the 2008 financial crisis.