Prince William visits Earthshot Prize finalist firm as his wife Kate continues cancer treatment and the King returned to public duties for first time since his diagnosis

Prince William visited an Earthshot Prize finalist company today as his father the King returned to public duties and his wife Kate continued her cancer treatment.

The Prince of Wales met the team at Low Carbon Materials in Seaham, County Durham, this afternoon to learn more about their product used in construction.

William, who is the Earthshot founder and president, will also hear about the work the firm has done since becoming a finalist in the environmental awards in 2022.

Three material science PhD students founded Low Carbon Materials with the aim of becoming a world leader in low-carbon and eco-friendly construction materials.

The Prince visited their research and development lab to be shown how it creates and tests concrete samples containing its product Osto, which is carbon-negative.

Staff also demonstrateD how the firm is incorporating waste carbon dioxide into their products, helping to further reduce their carbon footprint.

Since becoming an Earthshot finalist, Low Carbon Materials has signed a major partnership with National Highways to help reach the organisation reach its 2040 target of Net Zero emissions from construction and maintenance.

The firm's product Acla, developed with National Highways, and supported by contractors Skanska, enables the production of Net Zero asphalt which absorbs carbon as it is produced. 

It was used for the first time in a road resurfacing project in County Durham in March 2024.

Later, William will travel about 20 miles to open James's Place - a centre offering free, life-saving treatment to suicidal men in Newcastle.

It comes after a previously unseen portrait of the Prince and Princess of Wales was released by Kensington Palace yesterday in celebration of the couple's 13th wedding anniversary.

Kate, who is also undergoing treatment for cancer, married future king William in 2011.

The couple are facing their most difficult challenge so far amid the princess's diagnosis, with Kate appealing for time, space and privacy as she continues her treatment.

The photograph by Millie Pilkington - who took the most recent picture of the King and Queen to mark Charles's return to public duties - shows William and Kate on their wedding day.

The black and white image was posted on the Waleses' social media accounts on Monday, captioned '13 years ago today!'.

In an emotional message to the nation last month announcing her health news, Kate praised her husband for his support during 'an incredibly tough couple of months for our entire family'.

'Having William by my side is a great source of comfort and reassurance,' she said.

Last year, the Palace released a recent photo of the prince and princess to mark their wedding anniversary, showing them on bikes in the sunshine with their arms round one another.

But there was no new image of the couple this year as Kate continues her treatment for cancer away from the limelight.

Kate, 42, said in her video message how her diagnosis had come as a huge shock and that she and William 'have been doing everything we can to process and manage this privately for the sake of our young family'.

William returned to work following the Easter holidays when the Waleses spent quality time with their three children Prince George, Princess Charlotte and Prince Louis.

Louis celebrated his sixth birthday last week and Charlotte turns nine on May 2.

William and Kate released an unedited new photo of Louis straight to social media to mark the youngster's big day to thank well-wishers and avoid the uproar over the princess's digitally altered Mother's Day photo.

Also today, King Charles returned to public duties after doctors said they were pleased with his progress following cancer treatment.

Charles, who has been patron of Macmillan Cancer Support for more than 20 years, made a trip to University College Hospital Macmillan Cancer Centre in London..

He was accompanied by the Queen, who is president of cancer support charity Maggie's.

The visit was aimed at raising awareness of the importance of early cancer diagnosis and the couple heard about innovative research into the disease.

Aside from attending an Easter Sunday church service, the King has until now stayed away from public events.

Buckingham Palace gave an update on Friday on the King's condition and his return to public-facing duties.

The Palace said the King was still undergoing treatment for cancer and it was too early to say how long it would continue.

But a Palace spokesperson said 'His Majesty's medical team are very encouraged by the progress made so far and remain positive about the King's continued recovery.'

Charles's diary of forthcoming events will not be a full summer programme, with his attendance announced nearer the time 'subject to doctors' advice', according to the Palace.

In January, Charles spent three nights in hospital for a procedure on an enlarged prostate, during which his undisclosed cancer was discovered.