The King said he was impressed by the design of Europe’s first eco mosque and praised “all the care and attention which has been lavished on it”.
Charles, 77, was told about the environmental credentials of Cambridge Central Mosque as he toured the place of worship.
The King was greeted by cheers from well-wishers in the street as he stepped out of a maroon Bentley in front of the mosque on Monday afternoon.
He spoke to line-ups of dignitaries in a paved garden area with a fountain before moving inside the mosque, speaking to more line-ups of people in a first room.
Charles took off his shoes before walking through to a prayer hall where he spoke to more people.
He joked with some schoolchildren that he hoped he had not “ruined the holidays too much by dragging you in here”.
Back in the first room, having put his shoes back on, Charles unveiled a plaque marking the 75th anniversary of Cambridge being granted city status by King George VI.
Charles was then presented with a book about the mosque.
On its website, it is said that the mosque’s “emphasis on sustainability and high reliance on green energy make this Europe’s first eco-mosque”.
The building has solar panels on the roof and is heated and cooled by highly efficient heat pumps in the basement that produce more energy than they consume.
Grey water – such as from bathroom sinks – and rainwater are collected to flush toilets and irrigate the grounds.
Other eco features are that the building is naturally lit all year round by large skylights in the roof, supplemented by low energy LED bulbs.
After Charles unveiled the plaque, he said it had been a “pleasure” to visit the mosque.
Addressing those in the room, he said: “If I may say so I’m so impressed by the quality of the design, of all the care and attention which has been lavished on it, and the fact you have a purpose-built mosque here with the community centre attached.
“It makes a huge contribution I’m sure not only to the Muslim community but to Cambridge itself.
“So I congratulate you and I pray with all my heart that you continue with every possible success and that you continue your work together with other faiths in this area to set a remarkable example of integrated faith activity.”
He thanked those present for having him to visit.
As he walked back to his waiting car Charles spotted a group of children with flowers among the crowd in the street and took the time to speak to them, with security staff following him to the crowd.
The children gave him the flowers and the King spoke with them.
Angharad Walter, 45, of Cambridge, brought her nine-year-old daughter Indigo along after a friend told them that Charles would be visiting that day.
She said one of the mosque volunteers had gone to a local cafe and got some flowers that “they get gifted… from companies when they’re going to go past their sell-by date”.
“We were really surprised when he came over, it was really nice,” said Ms Walter.
Her daughter, Indigo, said it was “amazing” when Charles came across and “I felt so excited”.
“He was very nice and kind,” she said.
Zeynep Coskun, a trustee at the mosque, said it was “such an honour to be able to host the King here today”.
“He was very kind, he talked to everyone, he tried to understand everyone’s role,” she said.
She continued: “He was especially interested in the gardens and the environmental features of the mosque.
“This is an eco-friendly mosque.
“It’s a hot summer day but it’s still cool inside, it’s all passive heating and cooling.”
In a separate visit later in the day, Charles officially opened the city’s new Whittle Laboratory, a centre for disruptive innovation in net zero aviation and energy.
He had broken ground on the project in 2023 and also previously visited in 2020 and in 2022.
The original Whittle Laboratory, an aerospace and energy laboratory, was opened in 1973 by Sir Frank Whittle, who founded the company that invented the jet engine while still an undergraduate at Cambridge.
The Sustainable Markets Initiative (SMI), founded by the King in 2020, has helped bring together leaders from across sectors to support the lab, and to unlock investment and foster cross-sector collaboration.
