Ever since the invention of the British postcard in 1894, holidaymakers have been struggling to find the perfect message: something combining minimum words and effort with, perhaps, a saucy seaside joke.

“Weather is here. Wish you were wonderful” has long been a favourite, and a step up from “Having a lovely time” or “We saw this and thought of you”.

The ritual is long established: the postcard should depict the place it is from; it should contain some pithy remark and a smear of suncream or chip fat; and it should arrive a week after the sender has returned home.

The message need not relate in any way to the picture. Tom Phillips’s anthology The Postcard Century contains one from 1911 of a man strapped into an electric chair with the simple handwritten message: “I have been gardening all this week.”

Times Archive, 1913: Censorship of postcards

The vulgarity, semi-indecency and blasphemous suggestiveness are a standing menace to the morality of our young people

• Indecent picture postcards

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The point about a postcard is that anyone - the postman, your partner, your granny - can read it. If possible, they should be scandalised if they do. It is both private and public, in a peculiarly British way.

During the First World War the military came up with the field service postcard, on which the sender could simply cross out whichever statement did not apply: “Dear Mother/Father etc . . . I am quite well/have been wounded/admitted to hospital/ hope to be discharged soon . . .”

The mildly risqué postcard that reached its heyday in the 1950s relieved postcard senders of the requirement to think up their own rude jokes.

Donald McGill, perhaps the greatest of postcard artists, was a master of mild offence. Some of his 12,000 sketches were banned and he was prosecuted for obscenity, but his off-colour jokes were praised by George Orwell for sending a “chorus of raspberries to the censors”.

But in a way, the holiday postcard already sends a message without any words at all: “I am thinking of you enough to buy you this postcard, but not enough to bother to write a letter or telephone.”

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