Sir Sadiq Khan has been criticised after embarking on a 12,000-mile round trip to Brazil to attend a climate change conference - his fifth foreign trip of the year.
The London mayor has flown with City Hall aides to the “magical city” of Rio to attend the “biggest-ever gathering of mayors” at the C40 summit, a regular gathering of city leaders committed to responding to the “climate emergency”.
Research by The Standard found Sir Sadiq will have clocked up a total of 27,572 air miles this year by the time he returns to the capital at the end of the week - the equivalent of making 235 circuits of the 117-mile M25 motorway that circles Greater London.
When the flights taken by his aides are added, the total reaches an extraordinary 229,294 air miles incurred on mayoral visits this year - almost the same distance from Earth to the moon.
Tory assembly member Neil Garratt taunted the mayor by claiming he was “tackling climate change, one business class long-haul flight at a time”.
Tackling climate change, one business class long haul flight at a time. https://t.co/lITQR2kInJ
— Neil Garratt AM (@NeilGarratt) November 3, 2025
Sir Sadiq’s appearance in Rio came only hours after his own record at reducing emissions came in for criticism, with one of his Labour allies at City Hall warning that the capital was set to miss his 2030 “net zero” target.
Sir Sadiq, the co-chair of C40, used his opening speech on Monday to criticise Donald Trump, saying the US president was one of the climate “wreckers” that mayors needed to fight back against to reduce the threat of global warming.
In remarks that were not released in advance, Sir Sadiq essentially reactivated his long-running war of words with President Trump.
He said: “Famous among the wreckers is the President of the United States of America - someone who stood up at the United Nations, only a matter of weeks ago, and called the climate crisis a scam.”
In September, President Trump, who has previously branded Sir Sadiq a “stone cold loser”, wrongly claimed that Sharia law was in place in London.
Addressing the summit in Rio, Sir Sadiq spoke of his own policies, saying the ultra-low emission zone (Ulez) “has delivered massive environmental benefits” - as he promised more solar panels on school buildings in the coming year.
It can also be revealed that Sir Sadiq’s “trade mission” to Africa in July – the first by a London mayor – cost the London taxpayer almost £84,000.
Figures published by the Greater London Authority reveal that the Africa trip from July 14-19 – to Lagos in Nigeria, Accra in Ghana, and Johannesburg and Cape Town in South Africa – resulted in a total cost of £83,921 to the Greater London Authority.
This included £68,330 on flights, £11,418 on accommodation, £1,353 on ground transport and £2,818 on meals.
Sir Sadiq was accompanied by 10 staff in Nigeria and Ghana and 11 staff in South Africa. The trip involved five flights – with the mayor flying business class on the two overnight flights, from Accra to Johannesburg and the return from Cape Town to London.
He has also travelled to Poland – for the 80th anniversary of the liberation of Auschwitz – to the Mipim property conference in Cannes and to a gathering of world mayors in Paris this year.
In 2024, Sir Sadiq’s foreign excursions were to the United Nations General Assembly in New York (with aides, at a cost of £13,877), to the opening ceremony of the Paris Olympics (with six aides, at a cost of £4,901), and to Rome (with four aides, at a cost of £4,301) to meet the Pope.
He also took a return flight to Edinburgh at a cost of £515.
Sir Sadiq also visited New York in September 2023 with five aides as part of a C40 delegation at the UN climate summit. The travel bill of £14,626 was picked up by the C40.
In 2022, Sir Sadiq flew 7,000 miles to Argentina to attend another C40 conference.
Sir Sadiq’s 12,000 round trip to Rio is also on C40 business – the mayor is co-chair of the group of about 100 cities that are committed to tackling climate change.
The three-day summit of about 300 mayors is at least the 20th foreign trip undertaken by Sir Sadiq since he became London mayor in 2016.
The event is a precursor to the UN climate change conference COP30 that is being held in Belem, Brazil, which UK Prime Minister Sir Keir Starmer is due to attend.
On Monday, Sir Sadiq used his keynote address to re-heat previous comments about the “existential fight between climate wreckers and climate defenders”.
On Tuesday he will highlight the “disinformation” that mayors have to overcome, and will attend a “Game for Earth” football match that calls on sport’s leaders to “recognise and act on the threat of climate change”.
On Wednesday, Sir Sadiq will attend Prince William’ Earthshot awards, which showcase efforts across the globe to combat climate change.
But on Monday the London Assembly warned the mayor that the capital was “not yet on track to achieve its 2030 target to reduce emissions” and said there was a need to clarify what more would have to be done.
Leonie Cooper, the Labour chair of the assembly’s environment committee and one of Sir Sadiq’s most vocal supporters, said in a letter: “Key to this will be finding new ways to finance the transition to a low carbon, more climate resilient city.
“You have previously highlighted that your preferred pathway for achieving net zero by 2030 requires around £75 billion of investment.
“Despite the sizeable £1.1 billion you have mobilised and made available through the London Climate Finance Facility, this is less than 1.5 per cent of the total required, and still leaves a large amount that must be mobilised through other finance sources.
“When speaking to the environment committee, your officers also noted that the GLA does not hold figures on how much private finance has been mobilised since the initial assessment, and therefore does not know how large that gap now is.
“With less than five years to 2030, increasing climate finance rapidly and at scale must be a priority.”
The letter also expressed “concerns” in delays establishing the mayor’s Climate Finance Taskforce. “London’s net zero and resilience ambitions require a change in pace, and there is no time to lose,” Ms Cooper wrote.
Sir Sadiq’s decision to travel to Rio means he will miss the switch-on of the Oxford Street Christmas lights on Monday evening.
The cost of the trip for Sir Sadiq and his aides is expected to be covered by the C40, which receives funding from former New York mayor Michael Bloomberg’s charity, Bloomberg Philanthropies.
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