We know computing science teachers are rare beasts - headteachers hunt for them but rarely come away with the prize they seek - but now it has been suggested that they might actually be mythical creatures.

A small independent prep school in East Lothian, Belhaven Hill School, has caused a stir with its job advert for a computing teacher, which is headed: “Appointment of a purple spotted unicorn (or exceptional computer science teacher).”

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On social media, the advert is causing amusement, but the merriment is tinged with sadness.

Responding to the advert, purple spotted unicorn (or computing science teacher) Mark Tennant tweeted: “Great advert, but sums up the issue with a lack of #compsci teachers in one!”

The shortage of computer science teachers

Meanwhile, Toni Scullion - an even rarer beast, a female computing teacher  - commented: “Very sad and true”.

On exam results day this year, Tes Scotland reported that there had been a 21 per cent drop in entries for Higher computing science compared with the previous year. Responding to the news, teachers blamed - in part at least - the dire lack of computing science teachers.

Camilla Gray Muir is the chair of the Belhaven Hill School board of governors. This was the school’s first attempt to recruit a computing teacher, she said, but competition was stiff - 60 other schools were advertising similar roles.

So far, the school had received half a dozen expressions of interest in the role and she was glad the advert was making people smile, she said.  

She added: “The reality is if you have a good computing degree, it takes a pretty special person to say, ‘I have a vocation and I would like to teach young people,’ and ignore the money that can be earned in the private sector. We are completely realistic about the challenges but we are looking for someone exceptional - that’s something we won’t compromise on - and the application period, which does not end until December, reflects that.”

Ms Gray Muir explained that “purple spotted unicorn” was a tongue-in-cheek term used in the tech industry to refer to a job specification that would be tough to fill.