It could be viewed as another important indication that he is doing well with his cancer treatment after he was seen shaking hands with crowds at Easter.

Since announcing his diagnosis in February he has been advised by doctors not to carry out public-facing engagements.

But it's understood that officials, as part of normal forward planning, are now factoring in the possibility of the King meeting slightly larger groups of people from the end of April, into May.

It comes as the King welcomed the Governor of the Bank of England Andrew Bailey to Buckingham Palace, who presented him with the first bank notes featuring his portrait as monarch.

It is traditional that the sovereign receives the first serial numbered notes of a print run of banknotes (effectively serial number 01). The Bank has now produced £5, £10, £20, and £50 notes.

The image of the King which appears on the notes is based on a portrait that was provided by the Palace to the Bank of England.

This was then turned into an engraving, and designers worked from this to create the image on the notes.

The notes will enter circulation on the 5 June, but the Royal Household has insisted this should only happen gradually.

The new notes will only replace worn or damaged Queen Elizabeth II notes to minimise the financial and environmental impact of this change.

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The fact that the palace is continuing to plan ahead for the King's future engagements is nothing new, and there is obviously the caveat that things may have to change depending on his health.

Reports last week that the monarch still wants to push ahead with a trip to Australia and New Zealand at the end of the year to coincide with the Commonwealth heads of government meeting in Samoa is one example; the palace insists nothing has changed and that this has always been a possibility, depending on how he is.

Suggestions he may be well enough to start meeting larger groups is in no way confirmation of whether he will be able to attend any of the large traditional royal events this summer, such as Trooping the Colour, but it will be viewed by many as a positive sign about his health.

The King has regularly welcomed individuals to Buckingham Palace for small audiences in recent weeks and has been carrying out his constitutional duties behind the scenes, alongside receiving treatment.

On Easter Sunday he surprised everyone by unexpectedly walking up to crowds outside Windsor Castle to shake hands and chat with those who'd come out to see the royal family.