Bill Nighy, Stella McCartney, Brian Cox and Annie Lennox are among the high-profile figures urging Rishi Sunak to commit funds to lower-income countries dealing with devastation caused by the climate crisis.

A host of celebrities, which also includes Bella Ramsey, Mikaela Loach, Maxine Peake and Paloma Faith, collaborated with Oxfam to sign an open letter, delivered to the Prime Minister as Cop28 starts in Dubai on Thursday.

One of the key topics on the agenda at this year’s UN climate summit will be rich countries promising finance to poorer countries facing the worst impacts of global warming after the agreement to establish a Loss and Damage fund at Cop27 last year.

The letter said: “It is a gross injustice that those least responsible for the climate crisis are suffering its worst impacts – facing poverty, hunger, and ever more scarce resources.

“Following the historic decision at COP27 last year to establish a Loss and Damage fund to help communities in countries most vulnerable to climate change deal with its devastating consequences – one of the key questions for this year’s summit is: who will pay?”

It cites East Africa as an example of one of the regions worst hit by global warming, climate-induced drought, flooding and ongoing conflicts, which has left 26 million people without enough food to eat since their animals have died and crops have failed.

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Stella McCartney has signed the letter (Ian West/PA)

The letter also calls on Mr Sunak to hold the biggest and richest polluters, like fossil fuel companies and the super-rich, to account by taxing them more in order to raise the funds needed.

It said: “From increasing taxes on the super-rich, to ending the millions in tax relief that the fossil fuel industry receives each year, the UK could have raised an extra £23 billion last year.

“This money could be used to ensure a fair switch to renewable energy – reducing bills and emissions – as well as being used to help communities, such as those in East Africa, worst-hit by climate change to adapt and recover.

“The UK Government can and must do more. We should be leading by example and accelerating our path to a fossil fuel free future.

“The biggest and richest polluters have caused – and continue to cause – irreversible damage to our planet, and it’s only fair that they are the ones footing the bill.

“A better future is possible, but we cannot afford any more delays. Now is the time for action.”

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Brian Cox is among those calling on Rishi Sunak to commit to climate funds for poorer countries (Suzan Moore/PA)

Other signatories include Dominique Palmer, Jeremy Irons, Romola Garai, Livia Firth, Daniel Lismore, Hilda Flavia Nakabuye, Lavetanalagi Seru, Dara McAnulty, Tori Tsui and Zamzam Ibrahim.

Adding his signature to the letter, Pirates Of The Caribbean star Nighy said: “It is fundamentally wrong that those bearing the brunt of the climate crisis – people whose lives have been destroyed by intense droughts, floods, and storms – are those least responsible for climate change.

“The UK Government can and should be stepping up.

“The Prime Minister must ensure the biggest and richest polluters pay their fair share for the damage they have caused.”

Oxfam said the public can also add their names to a petition, calling on the Prime Minister to fairly tax the biggest polluters.

A Government spokesperson said: “The UK is a global leader in the fight against climate change, directly supporting over 100 million people cope with the effects of climate change since 2011.

“This commitment is backed by £11.6 billion over five years, including over £1.5 billion investment to the Green Climate Fund. We will press for further urgent action with leaders from across the world at Cop28.

“Alongside our international partners, the UK has agreed robust recommendations on loss and damage and will continue to press for urgent action in this area. We will set out more detail at Cop28.”