Among the lucky few chosen as Earthshot Prize finalists there is an awareness that such recognition, as life changing as it is, marks the beginning of a long road.

For Gunnlaugur Erlendsson, chief executive of Enso, a UK-based company that makes sustainable tyres for electric vehicles, the involvement of the Prince of Wales is motive enough to succeed.

“We aim to make him proud,” Mr Erlendsson, 48, told The Telegraph.

“We’re all excited, we’re all start-ups. And, you know, he has built the best prize on the planet, for the planet, so we should really recognise his efforts.”

There can be no doubt about the Prince’s personal commitment to the Earthshot project, the level of his involvement or his specific knowledge about each of the 15 finalists, whittled down from more than 1,000 applications.

Mr Erlendsson, nominated in this year’s Clean Our Air category, knows that tyre pollution is hardly a hot topic, or one that might easily capture the public imagination.

But when he met William, 41, he was taken aback by his interest. The Prince had certainly done his homework.

“He was incredibly well informed about what we were doing, it was a breath of fresh air to talk to someone who already knows about tyre pollution and so we really grabbed it by the horns,” he said.

“He was really aware that this was a topic that wasn’t widely discussed in the media in general. We touched upon the whole focus of the Earthshot Prize, which is to bring not just problems but optimism and solutions.”