The Government is not doing enough to meet its climate change obligations and the Prime Minister has “sent mixed signals” to international partners, his official advisers have warned.

The Climate Change Committee said perception of the UK around the world as a leader on green issues was hit after Rishi Sunak weakened some of the country’s policies.

“The international perception of the UK’s climate ambition suffered from mixed messages following announcements on new fossil fuel developments and the Prime Minister’s speech to soften some net zero policies,” the committee said.

It came in a report from the group into the progress made at the Cop28 summit in the United Arab Emirates in December.

As the world faced the hottest year on record and carbon dioxide emissions reached their highest level, negotiators made some progress at the meeting, the committee said, but the UK’s role at the forefront of global efforts to fight climate change was damaged.

“The Prime Minister’s net zero speech in September 2023, and decisions to approve a new coal mine and license new oil and gas production, have contributed to a perception of slowing UK climate ambition by members of the international community,” it said.

“This is despite subsequent positive policy announcements.”

The positive announcements include a rule which effectively forces car and van manufacturers to ensure a Government-mandated proportion of their vehicles are electric.

There was also extra help for households to switch away from gas boilers and towards heat pumps, which run off electricity.

But the committee called for much more action to ensure the UK meets interim goals along the way to become net zero by 2050.

It said renewables had to be rapidly deployed, adding that the rollout of solar panels and onshore wind turbines is “progressing too slowly” because there are barriers in the planning regime and it takes too long to link to the electricity grid.

The Government and National Grid have recently started taking steps to speed up grid connections.

The committee also said the Government should limit more oil and gas from being produced from UK waters.

“Were all countries with fossil fuel reserves to increase future fossil fuel production, there would be an oversupply that would pose a risk to the aims of the Paris Agreement,” it said.

The committee said the rate of emissions reductions must quadruple from 1.2% to 4.7% a year, excluding electricity supply, and that tree planting and peatland restoration “have been too slow and urgently require scaling up to meet UK emissions reduction targets”.

Professor Piers Forster, interim chairman of the Climate Change Committee, said: “The UK played an important role in this hard-fought Cop28 outcome.

“We may be further into the decarbonisation journey than many nations, but the obligation on every country is now to push even harder.

“This also frames the economic challenge for the UK. We must rapidly replace fossil fuels with low-carbon alternatives to get back on track to meet our 2030 goal.

“The UK could set a powerful example of tackling climate change and reducing our insecurity to climate impacts.

“The new global adaptation framework goes further than our own so I urge the Government to lean into its global role with an even stronger demonstration of domestic ambition.”

The Government said: “The UK is leading international action, delivering an agreement to transition away from fossil fuels and as one of the largest contributors to the loss and damage fund.

“We are the first major economy to halve our emissions, have some of the world’s most ambitious legally binding targets, and have over delivered on every carbon budget to date, while our significant investment in the UK’s world-leading clean energy sector – with 40% of our electricity now renewable compared to just 7% in 2010 – is bolstering our energy security.”