She visited the Anna Freud Centre, a mental health charity for young people

The Duchess of Cambridge resumed her royal duties in Islington on Thursday.

Catherine visited the Anna Freud Centre’s Rodney Street site in her first solo engagement since the birth of Princess Charlotte.

The children’s mental health charity wants to open a new centre of excellence in King’s Cross to integrate its research activities.

And the duchess gave her backing to the plans, which require £5m more fundraising on top of £20m already in the bank.

Chief executive Peter Fonagy said: “Currently, mental health care for young people is fragmented. It comes from different forms like the NHS, education and social care.

“What we are about is trying to bring all that together so we can create an integrated service focused on the child and in partnership with our research.

“The centre of excellence is about discovery and then being able to implement it. It will be a big step forward.”

Mr Fonagy added that he was hugely impressed by Catherine: “She was extremely astute, immediately understanding what we are trying to achieve and expressing the hope that our kind of service would be available more broadly.

“Of all the visitors we have had over the years, she was the person that impressed me most with her genuine interest and concern.

“It’s enormously valuable for us, and the young people who we work with, to have her backing.”

Leeann Skerratt, 30, of Hackney, and son Alfie, 12, also met the duchess on Thursday. Alfie has obsessive compulsive disorder (OCD) and has been attending the centre’s key stage three school classes since the start of term.

Ms Skerratt said: “His former school just couldn’t cater for him. There were no special needs schools around, so I was asked if I wanted to try something new and visit the Anna Freud Centre.

“I have been coming in with him every day, which gives him confidence as his anxiety can be up and down. It has helped so much.

“There’s no pressure on the pupils at all. It’s a slower pace than at normal school, but the way they approach it means the children get more done.”

Like Mr Fonagy, she had nothing but admiration for the duchess: “I was really jittery before meeting her. But she was very down to earth and seemed genuine with her questions, and they way she took part in demonstrations.”