Three sad words signal grim Kate Middleton update.

When members of the royal family talk to the public, the strangest trifles and details can come out of their mouths.

Last week, Prince William revealed that he thinks it is “very important” to talk to sheep, that he used to like lying down next to his horse and basically spooning it and that after a hard day of handing out MBEs, he can be found cleaning his children’s guinea pig cage.

Hopefully William, despite having sold his polo ponies years ago, still has at least one filly to spoon because the latest news about Kate suggests that she won’t be seen in public for a very long time still.

On Tuesday, UK time, King Charles, who like his daughter-in-law is also being treated for cancer, returned to public duties with such grinning gusto and vim and vigour that scientists should think about bottling his pep.

Britain's King Charles waves to crowds after to visit to the University College Hospital Macmillan Cancer Centre in London on Tuesday. Picture: HENRY NICHOLLS / AFP

Britain’s King Charles waves to crowds after to visit to the University College Hospital Macmillan Cancer Centre in London on Tuesday.

So, with one Windsor patient cleared to return to work, when might the eager lenses of the press and the wall of iPhones being held aloft and the internet and the world get a peek of Kate again? When might the princess be well enough to get back to her day job of being driven in an armoured Range Rover to Do Her Bit?

Ages. Ages and ages, it sounds like.

The Times’ assistant editor Kate Mansey has now reported that “Kate is expected to be away from public duties for some time.”

And it’s those last three words, “for some time”, which we need to take note of.

If we run the numbers and look ahead, it could well be, at least four, if not five, months at the very earliest that Kate returns to the public eye.

Next week will see the kick off of royal garden party season, signalling the starting gun being fired on the royal family’s busiest season.

Between now and July there will be, at the least, the palace garden parties in London and Edinburgh, the Chelsea Flower Show, Royal Ascot, the Order of the Garter day, Trooping the Colour, Wimbledon and the 70th anniversary commemoration of the D-Day landings in Normandy.

Normally, we would be looking at several months of peak Kate exposure.

Kate looks set to be noticeably absent from any public outing for the foreseeable future. Picture: Jordan Pettitt / POOL / AFP

Kate looks set to be noticeably absent from any public outing for the foreseeable future.

This year, given the “for some time” line, it seems likely there will be no Kate, no Kate, no Kate, no Kate, no Kate, no Kate, and, you’ll never guess, no Kate at each of these events.

If this is what plays out then, the very earliest we might see the Princess of Wales return to work would be in September, after the Windsors’ take their annual six-plus week summer hols, a portion of which it is mandatory for them to spend in Scotland doing battle with gorse prickles.

With Charles’ relaunch this week, what is clear is that Buckingham and Kensington Palaces have adopted opposing strategies as their principals face down the ‘C’ word.

In February, with the King’s doctors having ruled out him going anywhere near the germy masses, His Majesty has ramped up his social media appearances with the official royal family accounts spitting out a steady stream of shots showing besuited (no elasticised lounging pants even for a sick monarch) the 75-year-old hard at.

Meanwhile, the line being put about the place has been that even when the King is not doing these ambassadorial meet-and-greets (and an aide is patiently answering his question about what ‘an Instagram’ is) he is busy beavering away at State documents and having meetings with his private secretary and eminence grise, Sir Clive Alderton.

Both Charles and Kate are facing cancer battles. Picture: Max Mumby/Indigo/Getty Images

Both Charles and Kate are facing cancer battles.

Now, after only three months, Charles has gotten the medical green light to throw himself back into the thick of it this week, with him and Queen Camilla visiting a London cancer centre and looking happier than that one time an overeager equerry offered to burn down the Tate Modern for him.

This campaign of maintaining maximum visibility is the opposite of that adopted by Kate, who has been kept more firmly under wraps than someone who has gone into witness protection. (Windsor protection?)

Here we are in May and the princess has been seen on only four occasions: In that controversial Mother’s Day Franken-photo; as an instinct blobby shadow in the back of a car with William; in a short clip with William at the Windsor Farm Shop, the 21st century’s answer to the Zapruder footage; and in her 22 March video revealing that she has cancer and is undergoing preventive chemotherapy.

The Princess of Wales in a video revealing she is undergoing treatment for cancer.

The Princess of Wales in a video revealing she is undergoing treatment for cancer.

The princess now exists in a complete and utter informational black hole that probably requires the Hubble Telescope to penetrate.

Aside from the Princess of Wales’ March video, there has been a complete dearth of new information about how she is faring or when the world can tentatively expect to see her floating around a Hereford childcare centre in a turquoise McQueen blazer while tiny faces look up at her, agog.

Mansey’s “for some time” is the closest thing to even the most remote of pointers about how the rest of the year might unfold.

If ever there was a year that Kate deserved a truly excellent anniversary present, it’s this one but given Prince Binoculars’ track record, I have my doubts. The traditional gift for marrieds who have made it this long is lace. Heaven forbid if he spent Sunday night gift-wrapping a set of doilies.