According to Buckingham Palace, the King’s recovery has reached a very positive stage and he has “responded exceptionally well to treatment”, so much so that doctors will now move his treatment “into a precautionary phase”.

The regularity of treatment is going to be significantly reduced – but the King, 77, is not described as being in remission or “cured”.

“Today I am able to share with you the good news that thanks to early diagnosis, effective intervention and adherence to ‘doctors’ orders’, my own schedule of cancer treatment can be reduced in the new year,” the King said in his speech.

The video message, recorded in Clarence House two weeks ago, was played in the Stand Up To Cancer show on Channel 4 on Friday evening, in a fundraising project run with Cancer Research UK.

The campaign encourages more people to get tested for cancer and to take advantage of national screening schemes – and the King’s message emphasised the importance of checks to catch cancer at an early stage.

“I know from my own experience that a cancer diagnosis can feel overwhelming. Yet I also know that early detection is the key that can transform treatment journeys, giving invaluable time to medical teams,” said the King.

Early detection could be a lifesaver, he said: “Your life, or the life of someone you love, may depend upon it.”