Former New Zealand prime minister Jacinda Ardern has joined the board of trustees for the Prince of Wales’ environmental award.

Ms Ardern, 42, resigned in January after six years in charge, saying she did not have “enough in the tank” to continue.

William created The Earthshot Prize in 2021 to support projects aimed at protecting the planet.

Scheduled to run annually until 2030, winners receive a £1 million grant for their environmental work.

William said: “It is an honour to welcome Jacinda to The Earthshot Prize team.

“Her lifelong commitment to supporting sustainable and environmental solutions, along with her experience as Prime Minister of New Zealand, will bring a rich infusion of new thinking to our mission.”

He continued: “Four years ago, before The Earthshot Prize even had a name, Jacinda was one of the first people I spoke to.

“Her encouragement and advice was crucial to the prize’s early success.”

In September 2022, Ms Ardern spoke on behalf of William at The Earthshot Prize Innovation Summit in New York following the death of the Queen.

She said she was “humbled and excited” to work with the Earthshot team.

“Since its inception, I’ve believed Earthshot’s power to encourage and spread not only the innovation we desperately need, but also optimism,” she said.

“Solutions are within our reach if we invest, support and accelerate them globally.”

The board of trustees is chaired by Christiana Figueres, co-founder of Global Optimism and former UN climate chief who was responsible for the delivery of the Paris Agreement on Climate Change in 2015.