They are in Sidcup, perhaps, or verdant East Cheam - dotted across a grey island nation that from here seems remote and eccentric. The customers have rung a number in the UK to check their mobile telephone bill, or to ask about a new product or service. They are, for the most part, spectacularly unaware that their inquiry has been routed thousands of miles away to an Indian call centre, which serves rotis in its upstairs canteen and has a good view from the roof terrace of a giant lotus temple. Not, of course, that there is much to give the game away. The subterfuge is truly magnificent.
Nothing is left to chance.
Here, recruits receive a 20-hour crash course in British culture. They watch videos of soap operas, including The Bill, Emmerdale, Brookside, Coronation Street and EastEnders, to accustom them to regional accents. They are told who Robbie Williams is. They learn about Yorkshire pudding. And they are taught about Britain's unfailingly miserable climate.