Former US vice president Al Gore and the car giant Ford were among the biggest critics of the prime minister's new "pragmatic" approach to cutting emissions in a day of high political drama.

Mr Sunak insisted he was standing by the legally binding goal of hitting net zero by 2050 despite making changes including:

• Delaying the ban on new cars and vans running solely on petrol and diesel from 2030 to 2035
• Weakening the plan to phase out gas boilers from 2035 so households that will struggle the most to switch to heat pumps will not have to make the change
• Putting back the ban on boilers relying on heating oil in off-grid homes from 2026 to 2035
• Scrapping the requirement of energy efficiency upgrades to homes, which a landlords' organisation welcomed as meaning they will no longer need to spend "substantial sums of money".

Politics Live: Reaction as PM reveals major net zero changes

Mr Sunak insisted he was taking a "more pragmatic, proportionate and realistic approach that eases the burdens on families" and claimed other politicians were not being honest about the cost of green policies on individuals.

However, he was accused of peddling a "false argument" with critics saying clean energy will make bills cheaper and boost jobs and investment.

Chris Norbury, the chief executive of the E.ON energy firm, said "there is no 'green vs cheap' debate" and Mr Sunak's U-turns will "delay the vital work of transforming our economy".

He said companies wanting to invest in the UK need "long-term certainty" while communities now risk being condemned to "many more years of living in cold and draughty homes that are expensive to heat".

Car company Ford led the business backlash over the delay to the diesel and petrol ban.

Its chief executive Lisa Brankin said: "Our business needs three things from the UK government: ambition, commitment and consistency. A relaxation of 2030 would undermine all three."

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Ian Plummer, commercial director at Auto Trader, added that both industry and drivers have been left "high and dry" by "sacrificing the 2030 target on the altar of political advantage".

He said research shows only half of people could see how an electric vehicle (EV) could fit into their lifestyle and "we should be positively addressing concerns over affordability and charging rather than planting seeds of doubt".

PM 'sided with landlords'

Landlords welcomed not having to spend more on energy efficiency improvements to homes - a move Mr Sunak said would protect renters who may have faced the costs passed on to them.

But the National Housing Federation, which represents housing associations in England, warned scrapping targets "could lead to people facing higher bills for years to come".

According to their research, retrofitting homes would save social housing residents on average 40% on heating bills.

A similar warning came from the Energy and Climate Intelligence Unit (ECIU) which estimated cancelling energy efficiency regulations for the private rental sector could cost households almost £8bn in higher bills over the next decade.

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ECIU energy analyst Jess Ralston said: "The PM has sided with landlords over renters, putting their energy bills and cost of living up by ducking the improvement of rules on energy efficiency.

"That doesn't make any sense when excess cold in homes costs the NHS £1.2bn per year and renters are amongst those with the lowest incomes."

The changes have also sparked a political row with senior Tories lining up to criticise the prime minister.

Tory row erupts

Sir Alok Sharma, who was the president of the COP26 climate summit, told BBC Radio 4's Today programme: "I think it'd be incredibly damaging for business confidence, for inward investment, if the political consensus that we have forged in our country on the environment and climate action is fractured.

"And, frankly, I really do not believe that it's going to help any political party electorally which chooses to go down this path."

Boris Johnson and Conservative peer and environmentalist Zac Goldsmith also urged Mr Sunak to think again, with the latter even demanding a general election over the "economically and ecologically illiterate decision".

However, the plans were supported by the likes of Liz Truss and Jacob Rees-Mogg.

Although Mr Sunak insisted the changes were "not about" politics, the shift on green policies is being interpreted as a bid to create dividing lines with Labour ahead of a likely general election next year.

Some Conservatives believe rowing back on green policies could be a vote winner given their narrow success in the summer's Uxbridge and South Ruislip by-election, which was won largely through a campaign against the expansion of the Ultra Low Emission Zone (ULEZ) charge in London.

Labour 'relishing' chance to go 'toe to toe' on net zero

Labour said it was "relishing" the challenge of going "toe to toe" with the Tories over net zero at the next election as it promised to reverse the most incendiary of all the prime minister's promises - to move back the date to ban new petrol cars.

Ed Miliband, the shadow net zero secretary, also said the party did not support watering down obligations on landlords to improve the energy efficiency of rental homes, though he refused to lay out a position on phasing out gas boilers - saying that will be set out in due course.

Mr Miliband, asked at a Politico Q&A event whether the next election could become a de facto referendum on net zero, said: "I relish the prospect of going toe to toe with this government on saying who can make this transition work economically for the British people.

"Because the idea that Rishi Sunak - who is seen as out of touch, has delivered the biggest cost of living crisis in a generation - is the answer to the question of who is going to implement the green transition in a fair way, I mean, come off it frankly."