On Singapore’s swanky Orchard Road you’ll find shiny malls of glass and steel occupied by designer stores - Cartier, Prada, and the like.

But in one ageing, run-down building, Orchard Towers, you’ll find sex shops and girlie bars: its first four floors are notorious as a place where prostitutes ply their trade.

Yes, even gleaming Singapore has its grimier side. Granted, this is on the whole, a city which is both literally and metaphorically clean.

Here you’ll often see gardeners in the wide flowerbeds that line the streets, polishing the leaves of individual plants; here litter is something to be remarked on.

Here too, uniquely in the region, corruption in public life is not tolerated. As to private behaviour, there are 'outrage of modesty' laws so strict that men can be hauled up for offences not much worse than brushing against a woman’s bum on a dancefloor.

And yet there are also places where Singaporean spotlessness gives way to dirt. Places like Geylang, a red light district well off the tourist map, and Orchard Towers, with its so-called “four floors of whores".

Prostitution in Singapore in itself is not illegal, but various prostitution-related activities are criminalised such as public solicitation.

I thought writing about the four floors would make an interesting change from writing about tamer aspects of life in Singapore.