After a lengthy period of absence, King Charles is planning to resume public duties possibly as soon as next month, sources close to him told Vanity Fair.

Following a cancer diagnosis earlier this year, Charles has been undergoing outpatient treatment at a London clinic, forcing him to pause royal engagements. While he has continued to carry out state duties including Privy Council meetings and weekly audiences with British Prime Minister Rishi Sunak, he has not carried out public engagements as he recovers between treatments.

Charles’ last public appearance was on Easter Sunday when he attended church services with Queen Camilla and members of the royal family. The monarch, who was photographed with Camilla leaving church in Scotland on Sunday, has appeared in good health. While Buckingham Palace has not confirmed when the king will return to work, sources close to the monarch say he is recovering well from his treatment and is looking forward to taking part in some key forthcoming engagements.

With a busy summer calendar, King Charles plans to attend Trooping the Colour on June 15 as well as Royal Ascot the following week. The key events will mark Charles’ official return to work, however, if he is given the green light by his medical team, he may carry out public engagements before then.

“At the moment HRH is doing very well and responding very well to treatment,” says a royal source. “He is very keen to get back to public-facing duties before June if he can. He is doing well but is frustrated more than anything else that he has had to take time off. He is being a good patient but not always a patient one.”

Adds the source: “What he wants is to be back at work meeting the public and doing what he loves. That is the bread and butter of what the royal family does, and the king is very keen to be back out. He is determined to be at Trooping and at Royal Ascot if not every day then for at least one hopefully two days. He is also looking forward to the palace garden parties.”

King Charles is currently in Scotland and will return to England next week. Adds the source: “He has been responding very well to treatment and is very positive about his health. It is wonderful to see him so optimistic.”

While he has lost weight during his treatment, the king has been well enough to carry out desk work and correspondence throughout. Last month, he met Chancellor of the Exchequer Jeremy Hunt ahead of the Spring Budget announcement and he continues to read his daily red boxes of official paperwork. However, when he resumes public engagements, adjustments will be made to his schedule. Charles will have to take on fewer engagements and has been advised to opt for outdoor events where possible so he is not in close contact with members of the public.

Buckingham Palace has said that planning for future engagements continues and is subject to doctors’ advice. According to one aide, decisions about future engagements will be made “nearer the time and making allowance for adaptations as necessary, or not.”