Boris Johnson is set to announce ambitious cuts to the UK’s greenhouse gas emissions – but has been warned that action to deliver the reductions is urgently needed.

The Prime Minister is understood to be preparing to commit to cutting emissions by 78% by 2035 compared with 1990 levels, in line with the recommendations of the Government’s climate advisers.

The announcement is scheduled to be made ahead of a major US summit on Thursday where President Joe Biden is expected to set out a new US target for reducing emissions.

It would mark a significant step forward on the current UK commitment to cut emissions by 68% by 2030 – already seen as one of the most ambitious plans among developed nations.

But environmentalists said it would make the Government’s £27 billion road building scheme and airport expansions even harder to justify, and that measures to slash emissions from homes and transport should already be under way to deliver the commitments.

The new target is in line with the advice of the Climate Change Committee, published last year, for the Government’s sixth carbon budget.

It would put the UK on track to meet its legal goal of a 100% cut by 2050, or “net zero”, which requires cutting emissions to as close to zero as possible and taking steps such as planting trees to offset any remaining pollution.

It is expected to include emissions from aviation and shipping for the first time.

In its report, the committee said setting its recommended target for 2035 would effectively bring forward the UK’s previous commitment to get to an 80% reduction by 2050 by 15 years.

To meet the target, the committee said that there would have to be more electric vehicles, an extension of offshore wind power generation, a reduction in meat and dairy consumption and the planting of new woodland.

The pending move comes at a time when the Government is anxious to give a clear lead on climate change in the run-up to the international Cop26 talks the UK is hosting in Glasgow in November.

The Department for Business, Energy and Industrial Strategy said that ministers would be making an announcement “shortly”.

Electric car charging
The Climate Change Committee said reaching the target would require more widespread use of electric vehicles (John Walton/PA)

For Labour, shadow business secretary Ed Miliband said the Government had repeatedly failed to match ambitious promises on emissions with effective action on the ground.

“While any strengthening of our targets is the right thing to do, the Government can’t be trusted to match rhetoric with reality,” he said.

“We need a Government that treats the climate emergency as the emergency it is.

“This year, as hosts of Cop26, the UK has a particular responsibility to lead the world and show the way forward for a greener future. This Government isn’t up to the task.”

Greenpeace UK’s head of politics, Rebecca Newsom, said the announcement could be the boldest pledge in the week of the US summit, which is expected to see a number of countries increase their ambition on climate action.

“This major shift in gear from the Government makes destructive projects like new road building and airport expansion even harder to justify.

“Targets are much easier to set than they are to meet, so the hard work begins now.

“In order to actually deliver on this commitment, new measures to slash emissions from homes and transport should already be well under way.

“So unless the Government’s policies urgently fall in line with its ambitions, there could still be awkward questions for Boris Johnson at the global climate talks in the autumn,” she said.

Ed Matthew, campaigns director for the climate change think tank E3G, said an ambitious emissions reduction target would boost the UK’s diplomatic efforts to persuade other countries to do the same.

“The UK now has the opportunity to spark a global green industrial revolution, but ultimately its credibility will rest on action.

“It must now put in place the policies and investment needed to achieve the target. That is the mark of true climate leadership,” he said.