The most recent, it has to be admitted, didn't quite have the jaw-dropping impact of the one which not so long ago revealed that a swathe of the country exclusively associates the name Churchill with a nodding bulldog – and the catchphrase "Oh yes" to flog insurance – rather than V for victory, a cigar the size of a felled tree and fighting them on the beaches. The new poll is nonetheless worrying. Apparently, almost 70 per cent of us are incapable of identifying St Paul's Cathedral; less than 50 per cent know Trafalgar Square (presumably Albert Square registered a much higher mark) and just 62 per cent can pick out Hadrian's Wall. Hang on... it gets worse. A mere 27 per cent were able to connect Oxford to its dreaming spires; perhaps we've finally grown weary of Inspector Morse re-runs.

The good news? Four out of five of us recognise the Angel of the North. Antony Gormley, responsible for the sculpture, claims that we "want something more challenging in our art". But he would say that, wouldn't he? I think differently. If you dismiss the possibility that the entire survey was carried out in Gateshead, the average Briton's abject lack of intelligence about our most striking cultural landmarks is lamentable and embarrassing: a despairing sign that most of us don't see, don't care about or are at best ambivalent towards architecture and public art. What's really "challenging" as a result is the task of changing such perceptions. As a rule we don't take draftsmanship or sculpture too seriously until we viscerally dislike a building or statue. The Angel of the North warrants its iconic status because the sweep of Gormley's imagination created a work of instant, popular appeal. This, however, is a very small mercy indeed. For if we can't get people to appreciate – or even notice – the established art around them, we'll struggle to persuade them that it is worth preserving.

By coincidence, the survey's findings were published on the same day as another story broke. Gormley is to advise on a £1m memorial to the dead and injured of the 7/7 terrorist bombings. The juxtaposition of the two articles is ironic but timely. Public art with a specific purpose is a tightrope walk. It has to perform its solemn duty as a commemoration, but also succeed aesthetically. Along the way, from pen to chisel, there are nearly always disputes over design and setting. The end result is often a muddled, bland, unsatisfactory compromise, such as the Princess Diana Fountain. So Gormley's theory that we want our art to be "challenging" will be tested in the stone, marble or metal of the 7/7 tribute. More than likely, what will emerge is something "profoundly dignified", a euphemism for safe and uncontroversial. In the meantime, we can get on with the job of vigorously promoting our architectural heritage. Mind you, judging from an example of Dumb Britain I heard on the radio, it may already be too late to even try.

Questioner: Who built St Paul's Cathedral?

Contestant: Christopher Robin.

Piglet is apparently a dab hand with a spirit level.