Ian McMillan: The day Yorkshire erupted all over Britain

I'm referring, of course, to the Cloud of Volcanic Yorkshireness that enveloped the British Isles and parts of Northern Europe in April 1960. Perhaps the knowledge has been kept under wraps by officials in suits: well, I'm unwrapping it right now, and I don't care what you do to me! Unless it involves rusty pliers, of course.

On April 13, 1960, the long-dormant Maltby Volcano (situated round the back of the library, where they used to park the mobiles) began to smoke like an old bloke in the garden shed puffing on a pipe. This wasn't, in itself, unusual: every few years, the Maltby Volcano belched, breathed out a few sparks and then settled down to whatever the Maltby version of eternal slumber is.

April 13, 1960 was different: the smoke was thicker, the steam was hotter, the sparks were, well, sparkier. The police and the fire service were called and the nearby streets were evacuated. Nobody really knew what was going to happen next; if they had have known, they probably wouldn't have looked quite so calm. Cups of tea were shared and the odd biscuit was munched. It was t'calm before t'storm, if you get my drift.

At exactly 11.30 in the morning, the ground around the Maltby Volcano began to shake and rumble. In the library, books literally flew flapping from the shelves like Catherine Cookson Finches and Biggles

Birds. The police and the fire service stepped back in alarm, cups of tea were spilled and half-eaten biscuits dropped.

Suddenly the volcano gave a mighty roar, which some witnesses later said sounded like a giant EYUP! and a cloud of Volcanic Yorkshireness mushroomed into the air; passers-by commented that "it looked like a giant flat cap floating in the sky" or "it looked like a giant muffler floating in the sky" or "it looked like a giant whippet floating in the sky". Well, whatever it looked like, a cloud of Yorkshireness was spreading like Yorkshire Pudding batter all across the country, and the results were quickly spectacular and far reaching.

As far south as the Sussex coast, people were beginning to speak in Yorkshire accents. Cockney barrow boys and pearly kings on Smithfield market suddenly began to sound like minor characters from JB Priestley plays; "Cor Luvva Duck" was replaced by "Nar then sithee" as the Volcanic Yorkshireness settled over the land.

Scousers, Lancashire folks, Yellowbellies, Men of Kent, Kentish Men, Welsh people, Scots, visiting Americans and the Russian Ambassador all began to talk Tyke. A debate in the House of Lords resembled a late-night discussion at the Wombwell Pigeon Club, and a number of Debs about to be presented to London society became too distressed to speak when they found they were talking, in the words of one of them, "like my cleaner's cleaner's mother".

The Prime Minister, Harold MacMillan, had to go on live television the next day to make a statement to calm the trembly nation, but as he did so he found that, no matter how he tried, he couldn't stop his luxurious hair shaping itself into a flat cap shape on the top of his aristocratic head. As the red light went on and the camera rolled, SuperMac found that his normal mellifluous You've-Never-Had-It-So-Good tones began to twist and crinkle until he sounded like my Uncle Charlie who worked down Houghton Main pit. He cleared his throat and wiped his mouth with a massive tartan hankie but it made no difference: the nation was being addressed at a time of national crisis by a Wilfrid Pickles impersonator.

As the cloud of Volcanic Yorkshireness spread over the next couple of days, it began to affect other walks of life. Stockbrokers in the City of London were subject to irresistible urges to dig holes in the ground and attempt to extract coal from the mess of wires and pipes just under the pavement.

Top chefs replaced their entire menus with Yorkshire Puddings and Parkin and were surprised to find people queuing round the block for these culinary delights. For a couple of heady days, it felt like the country was reshaping itself, as the Queen made plans to relocate to Tong.

Then, as quickly as it had appeared, the cloud of Volcanic Yorkshireness dissipated due to strong winds from the East. The

nation's temporary madness was forgotten, and the holes in the ground were filled in and quail's eggs replaced fruit cake with cheese on the menus of posh eateries. The whole episode was forgotten, airbrushed from history, deemed by the powers-that-be to be a non-event that never happened anyway.

But I'm here to tell you that it did. And I don't care who knows. Write to the Yorkshire Post letters page if you recall the cloud of Volcanic Yorkshireness: let's right a small historical wrong!