Prince William has spoken out for the first time since his grandmother the Queen’s funeral on Monday.

The new Prince of Wales addressed a gathering in New York, where he had been due to attend the Earthshot Prize Innovation Summit. He said that he couldn’t be there in person due to the “saddest of occasions,” the Mirror reports.

William was originally due to make a solo trip to the United States on September 21, where he would have been joined by previous winners of the £50m global environmental competition. In a video broadcast on Wednesday, the Prince said he believed Elizabeth would have “been delighted to hear about” the summit.

He told those gathered: “During this time of grief, I take great comfort in your continued enthusiasm, optimism and commitment to The Earthshot Prize and what we are trying to achieve. Protecting the environment was a cause close to my Grandmother’s heart, and I know she would have been delighted to hear about this event and the support you are all giving our Earthshot Finalists – the next generation of environmental pioneers.

“Together in this room, are the people and organisations who will help us to achieve the Earthshot mission: to repair, restore and rejuvenate our planet within this current decade. That mission is not simple.

He added: “Together, we need to ensure the transition to sustainable solutions is the fastest and most endemic change the world has ever known. I know that by discovering, awarding, celebrating, and scaling solutions that repair and regenerate our planet we can inspire that urgent action.

“So today, as you hear the incredible stories of last year’s Finalists, I invite each of you to join me on this journey. Because this is just the start.”

The Earthshot Prize was founded in 2020 by Prince William and his Royal Foundation. It became an independent charity in July this year, with William as its president.

The second Earthshot Prize awards ceremony will go ahead this December in Boston, after last year’s inaugural event at Alexandra Palace in London. Prince William, his wife Kate Middleton and their two eldest children Prince George and Princess Charlotte all attended the state funeral at Westminster Abbey on Friday.

The Royal Family is still in its official 17 day mourning period for the Queen, announced by King Charles who said that the royals would not partake in any public engagement for the next week.