The Prime Minister has lashed out at countries who “really should know better” for “dragging their heels” on climate commitments made in Paris.

Speaking in the House of Commons on Monday afternoon, Boris Johnson hailed Cop26 as “the summit that proved the doubters and the cynics wrong” – as he said it kept alive the aim of limiting global temperature rises to 1.5C, and united the world in “calling time on coal”.

Mr Johnson told MPs that, for decades, tackling the coal problem “proved as challenging as eating the proverbial elephant”, but that in Glasgow the world “took the first bite”.

He also celebrated progress on “cars, cash and trees”.

But he said he was not suggesting “we can safely close the book on climate change”, and he could think of “nothing more dangerous” than “patting ourselves on the back and telling ourselves that the job is done”.

Mr Johnson said the job would not be complete until the whole world had reached net zero – and that he could not “claim to be certain that we will”, as certain countries that “really should know better” had been “dragging their heels on their Paris commitments”.

However he said that if those countries did fulfil their pledges, Glasgow would be remembered as the place where “the world began to turn the tide”.

Mr Johnson said the success of the Cop26 pact lay not just in the promises made, but the move from “setting abstract targets” to “adopting the nuts and bolts programme of work” to meet those targets and cut carbon emissions.

“We are now talking about the how rather than the what and getting into a habit of cutting CO2 that is catching on not just with governments but with businesses and with billions of people around the world,” he said.

“It is for that reason that I believe Cop26 has been a success and 1.5 is still alive.”

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However Labour leader Sir Keir Starmer said in response that the summit had been a “missed opportunity”.

“The Prime Minister has been the wrong man in the wrong place at the wrong time. And Glasgow has been a missed opportunity, a stumble forward when we needed to make great strides,” he said.

“More climate delay when we needed delivery. And 1.5C is now on life support. We still have the chance to keep 1.5C alive, but only with intensive care.

“We have to speak honestly about the challenge we face to rebuild the coalition that we need, and to take on the big emitters. We can and we must change course.”

The Prime Minister previously said his delight at any progress made at Cop26 was “tinged with disappointment”.

Cop26 President Alok Sharma was close to tears on a couple of occasions during an hours-long final plenary at the summit, including as he apologised to delegates for the way a change to the pact’s wording on fossil fuels was brought about at the eleventh hour.

Following a push led by China, and backed up by India, it was decided to change the language from accelerating the “phase out” of unabated coal to “phase down”, a move that prompted angry responses from European and vulnerable countries.

UK officials were surprised by this last-minute move.

Some observers have suggested China may have been caught unaware after references to coal within the text were not abandoned at an earlier stage.

But despite what was clearly a tough blow at the tail end of the summit, the UK is understood to view Cop26 as a hopeful story – in light of the number of countries that signed up to the agreement.

The Prime Minister also said today that Mr Sharma, who presided over the talks in Glasgow, now needed a “well-deserved break”.

But he added: “I don’t think any of us here will be able to hold him back as he sets off pushing countries to go further still and making sure the promises made in Glasgow are delivered not diluted.”