The Queen has shared an uplifting message about the “inspiring” work of volunteers.

Her message to mark Volunteers’ Week comes after her grandson, the Duke of Cambridge, revealed he has been secretly working as a volunteer supporting people contacting a crisis helpline developed by his Royal Foundation.

William has been working with Shout 85258 – a round-the-clock text messaging helpline.

The Queen hailed the “vital role of the volunteer” in the world today.

In her message, she said: “As Volunteers’ Week draws to a close, it is inspiring to reflect on the many thousands of people, who through their acts of generosity and kindness, have achieved so much for the greater good.

“I have been following with interest how men and women from around the world, including my own family, have been helping and recognising the vital role of the volunteer.

“I send my best wishes to all those who give themselves so freely and selflessly in the service of others.”

An image of William, Prince George and Princess Charlotte after they recently packed and delivered food parcels to isolated pensioners near the Sandringham Estate was also released by the palace.

Last month, William and Kate, the Duchess of Cambridge, marked the service’s first anniversary by speaking to some of its volunteers via video call, and William said: “I’m going to share a little secret with you guys, but I’m actually on the platform volunteering.”

Kate, the Duchess of Cornwall, the Countess of Wessex and the Duchess of Gloucester have all joined the NHS Volunteer Responders and have been making regular calls to people self-isolating in the community.

One of Sophie’s calls was to widower Harry Deboo, 89, of Liverpool, who recently had a triple bypass.

He said: “It was great to chat to the Countess of Wessex and really made my week. I have one son who doesn’t live locally, so I don’t get to see many people – especially now.”

He added: “She really listened to every word and it was great to share our lockdown experiences together!”

A royal source said the Cambridges would be carrying out official events via video calls for the foreseeable future, but they were hoping to resume visits in person at some point.

“As with other royal households we are looking at ways we can do physical engagements in the future in line with Government guidance,” the source said.

The biggest issue was trying to organise royal engagements in a way that did not attract crowds or put pressure on police resources, the source added.

The duke is one of more than 2,000 crisis volunteers who are trained to support anyone, whatever their crisis, chatting via text message and helping people sort through their feelings by asking questions, empathising and listening.

The Cambridges and the Duke and Duchess of Sussex helped to launch the crisis line in May last year, investing £3 million in the service through their Royal Foundation.

More than 300,000 text conversations have taken place between volunteers and people needing mental health support, with around 65% of those texting aged under 25.

It is understood that Kensington Palace had previously been reluctant to say whether William was volunteering for the service because it feared Shout might be overloaded by people hoping to discuss their troubles with the future king.

But Shout is now geared up to handle an expected increase in demand for the service.

The couple marked Volunteers’ Week by chatting with the Machynlleth Community Corona Response Group, and in a lighter moment the duke joked about coronavirus panic buying, asking: “Can any of you explain to me why all of us were bulk-buying toilet roll?”

More than 120 volunteers in the mid-Wales market town of Machynlleth and surrounding villages go shopping for neighbours, staff a telephone helpline, and cook and deliver nourishing meals for the vulnerable.

In the video call on Wednesday, William praised their efforts after the couple had spoken to 91-year-old great-grandmother Lynda Edwards-Ryley, who was lonely and isolated before volunteer Sadie Maud offered her support.

The duke said: “It’s National Volunteering Week and we want to say a big thank you from both of us. Thank you for all the volunteering you’re doing, thank you for all the time and all the effort you’re putting in.

“It’s been hugely rewarding and important that you guys are doing that and, as we’ve heard from Lynda, all of you have been a lifeline to all the people who you’ve helped in the area.”

The Cambridges also spoke to Conscious Youth, an organisation working with young people from mainly black and other ethnic minority backgrounds in West Yorkshire, and joked about the challenges of home schooling.

The couple have not disclosed if they have sent their children back to school, but William admitted some of Prince George’s coursework has proved daunting at times.

“I struggle with Year 2 maths,” he said.