Mainlanders, as a rule, know better than to openly protest against anything the govern-ment says; and, to be fair, they do have 5,000 years' worth of practice in mute submission. It's a question of survival.

However, when the municipal government of Shanghai decided in 2010 to outlaw the lovely tradition of wearing pyjamas in public, people did protest, and in the only way they knew how: by continuing to wear pyjamas in public.

How the officials must have been tying themselves in knots: here was the biggest showcase of Chinese greatness since the Beijing Olympics, namely the Shanghai World Expo, and people were insouciantly walking around in their jimjams. In front of the whole world.

The "big-character posters" so beloved of communists all around the world started appearing all over Shanghai: "Pyjamas aren't suited for going out the door; let's have a civilised Expo!"

If there is one word that features as regularly as "harmony" (meaning "do as we say") on such posters in the mainland, it's "civilised" (meaning "don't embarrass the country with your hick-from-the-sticks ways").

The Expo came and went and, as far as I know, the residents of Shanghai are still wearing pyjamas in public, perhaps a tad more gleefully than before.

The pyjama capital of China is a long way from Shanghai, though - it's in Guizhou province, which has never hosted a large international event. Or at least the duds of choice look like pyjamas: patterned jackets with matching trousers. They're not of the thin cotton or silk variety, however; rather, they're padded, like thermal underwear in reverse, as they're worn on top of other clothes in winter.

Teddy bears interspersed with stars and flowers seem to be the pattern of choice, although others involve blond princesses, palm trees and puppies. Women with elaborate hairdos and high heels look very comfortable swishing down the road or sashaying around the supermarket in their outdoor pyjamas.

His 'n' her PJs are naturally popular and, as ever, blue is for boys, pink or rusty red for girls.

The provinces are really like separate countries: in Guizhou, everybody wears pyjamas in public and coal-heated stoves are used as tables in restaurants. In neighbouring Sichuan, which is much colder, nobody wears pyjamas in public and the restaurants are as cold as morgues, with not a piece of coal in sight. I often wonder why. And another question: if pyjamas are street clothes, what do the people of Guizhou - and Shanghai - wear in bed?