Prince William and Kate, Princess of Wales, could risk their “unblemished relationship” with a new partnership. This week it was announced Jacinda Ardern has been appointed a trustee of the Earthshot Prize after she resigned as Prime Minister of New Zealand. But, journalist Dan Wootton warned the alliance is “dangerous” for the royals and “completely unnecessary” as they risk getting involved with politics.

Writing for MailOnline, Wootton has “picked her side in the increasingly bitter war of the Windsors”.

It comes after Ms Arden distanced herself from Meghan Markle and Prince Harry after she appeared in their Netflix Live to Lead series.

The former leader said the interview had been conducted two and a half years before the Sussexes got involved.

In a statement, her office said: “All communication throughout has been with the foundation (there has been no communications with the Duke and Duchess of Sussex regarding the project).”

Wootton claimed Arden going in favor of the Prince and Princess of Wales marks a “significant deepening of the toxicity” in their relationship with the Sussexes.

He added: “But, in the giddy excitement about notching up yet another major victory against his treacherous younger brother, I fear William has made his first mistake as Prince of Wales by aligning himself so closely with one of the world’s more divisive politicians.”

Announcing she was stepping down as Prime Minister, Arden said she no longer had “enough in the tank” to lead the country.

She said she was “humbled and excited” to be working on the Earthshot team.

Prince William Ardern’s “life-long commitment to supporting sustainable and environmental solutions” and her experience would “bring a rich infusion of new thinking to our mission”.

But Wootton claims William has been “badly advised” with the appointment.

He said: The late Queen would never have thought of signing on such a contentious Commonwealth PM just out of office as a key adviser.

“It’s alienating because, like it or not, over 50 per cent of New Zealanders ­­– and many millions around the world – think Ardern was a terrible leader.

“And it is tone-deaf to think otherwise, simply because said politician happens to be a media darling.

“There’s also a serious dose of hypocrisy connected to such a hiring.”

He continued: “Ardern’s rap sheet is lengthy and complicated, and I accept that the Prince of Wales may not be aware of it, given the sort of courtiers who surround him, but it’s important that he does his due diligence now and rescinds the offer to Ardern.

“Otherwise, he risks creeping ever more down the path of politics, damaging his well-deserved unblemished reputation.

“Trust me on this, Wills, as one of your most ardent supporters, Ardern isn’t worth that.”