Sir Sadiq Khan has conceded that London will not hit its designated Net Zero targets by 2030.
The Mayor of London pleaded with Cabinet ministers to hand over more power to devolved bodies and blamed stalling progress on over-reliance on fossil fuels.
Nevertheless, the Labour politician heaped praise onto having made "lots of progress" despite failing to fulfil his manifesto pledge from six years ago.
He lauded the introduction of the widely controversial Ulez scheme and the electrification of some London buses. Battery-electric and zero-emission buses make up almost 30 per cent of the capital's fleet.
Still, he blamed his lack of control over the energy grid for the missed target.
The bodies under the Greater London Authority's control are on track, from Transport for London (TfL) to the London Fire Brigade (LFB).
Sir Sadiq said: "A simple example – TfL uses its procurement power to change the market. If you think about the police, fire service, NHS – the public sector in London has the power to change the market.
"By 2030, we will have made lots of progress – we won’t get to, on current trajectory, Net Zero in London. We will get there for the GLA group, which is a big achievement considering where we started.
The Labour Mayor made the promise six years ago
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"What I’d like is more devolution.The grid has got to change – a lot of the problems we are having are because the grid relies on fossil fuels.
"If we can change that, the opportunities are huge.
"We’ve also got to retrofit buildings – we can’t give people renewables (in new buildings) and cheaper bills but then let it all out again."
Greens leader and London Assembly Member Zack Polanski took aim at the Labour Mayor for the "siloed" measures by the GLA.
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Zack Polanski criticised the admission
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The ex-hypnotherapist said: "The mayor is right to say London isn’t on course for net zero by 2030 – we should be targeting more effort at that now.
"And this should be non-negotiable. Climate science doesn't care about politics.
"There are so many other benefits London could have from the investment we need – cheaper energy, cooler homes and better transport.
"The Government should be supporting cities to get on and invest in tackling climate change."
Speaking during Mayor's Question Time at City Hall, Sir Sadiq ceded the "fair" criticism and said: "The funding comes from different pots of money, it’s frustrating.
"If we had an integrated settlement, monies devolved to London in one pot, we could have some joined-upness."
Central Government's spending review included handing to London its first integrated settlement, although the funding is tied to success in specific outcomes.
Sir Sadiq's promise to reach Net Zero in London by 2030 was far more ambitious than Westminster's amended goal of 2050.