'I suppose strictly speaking one should say the drawing room, as we do have a dining room to withdraw from and that's where the term comes from,' said Alexander. 'But sometimes I do tend to say sitting room, just because I hear it said so often,' he added, with the air of someone confessing to cutting virgins' throats at midnight.
Sarah, 22, Alexander and James, both 24, share the flat; Alex and James work in the City, Sarah works in a gallery. Alex and James are both Honourables. They are all products of expensive public schools - but everyone goes cross and cagey as soon as the S-word is mentioned.
'We are not snobs and don't want to be made out as a bunch of upper-class idiots,' snapped Alexander. 'We might have a certain way of looking at things, a certain attitude, but that doesn't make us any more snobbish than someone with a pit bull who lives in a council flat, drinks 10 pints of lager a night and has an equally strong attitude of his own.'
Post-Alan Clark, how much of an insult is it to call someone a snob? 'Mr Clark is not simply a snob, he is a bar-room snob,' sniffed Roy Hattersley; 'Alan Clark has exposed himself as a devious snob,' the Times snorted. But elsewhere, including in the Economist, snobbery was mentioned alongside 'intellectual zest, honesty and wit'.
'I really don't understand why everyone calls Alan Clark a snob,' said the Honourable James. 'He just isn't mealy- mouthed and hypocritical. Nobody really believes every single person is absolutely equal, and most people put themselves at the centre of the universe. Journalists,' he added darkly, 'are often pretty bloody pleased with themselves. I don't read any of the Sunday papers. Only the FT during the week.'
'I think twerps who drive gleaming Porsches with in-car CD players and mobile phones and say they live in 'Clarm' not Clapham are snobs,' said Sarah, smoothing back her gleaming straight fair hair. She is 22, but in her silk blouse with a neat scarf at the neck she could pass for a polished 30. Would she call such oiks the 'below- stairs' classes, a la Mrs Clark? 'Oh, no. Calling someone else common is absolutely the commonest thing one can do.'
The British snob has a strange pedigree; in the late 18th century the word merely meant a very below-stairs shoemaker or cobbler. But by 1848, when Thackeray published his Book of Snobs, it had come to mean someone who admired the upper classes and aspired to pass himself off as one. 'Crawling, truckling lackeys and parasites,' observed Thackeray, before happily confessing to being one.
In Our Mutual Friend, Dickens created the ghastly Veneering family with their 'bran- new' mansion and 'bran-new' money. In his diaries, Alan Clark describes Michael Heseltine as one who 'in Jopling's damning phrase, 'bought all his own furniture' '; Mr Veneering is similarly vulgar nouveau-riche. 'What was observable in the Veneerings was observable in the furniture - the surface smelt a little too much of the workshop and was a trifle sticky,' wrote Dickens.
By this century, rather than meaning the lower classes enviously peering up from under the stairs, a snob meant one of the upper classes surveying the masses from over the banisters. Nancy Mitford's collection of essays, Noblesse Oblige, written with tongue firmly in upper- class cheek and published in 1956, took up a Birmingham University professor's paper on U (upper-class) and non-U English usage (an extract from which appears elsewhere in this newspaper), and exposed the linguistic codes that kept the oiks in their places.
Serviettes, cruets, toilets and doilies were all beyond the pale. Fish knives were a grey area: Evelyn Waugh, contributing to Noblesse Oblige, pointed out that while the wife of a Master of Foxhounds would never use one, some august stately homes were positively awash with them. (No mention of the wives of judges or MPs.)
Some of these minefields have been defused over the last 40 years. Fish knives and cruets, according to James, Alexander and Sarah, are 'not really an issue any more'. Linguistic nuances, they claim, are no longer a necessary study for those wanting to make their way in society - though certain words still seem to carry the threat of instant social death. 'I personally would say loo rather than toilet,' said Sarah. 'Though if someone did say toilet, I wouldn't be too shocked.'
'I don't think toilet is a particularly attractive word and I would hesitate to use it,' says Meredith Etherington-Smith, editor-at-large of Harpers & Queen. 'But U and non-U - Nancy Mitford wrote it as a joke] Half the people who leave Eton have cockney accents and I know a marquis that you'd think was a garage mechanic. Yes, I'm a snob, but about excellence rather than social position.
'It's easier to get into society here than in America or France. Only wanting to move with your betters is a nasty, middle-class kind of snobbery. The upper classes get on with everyone.'
Who are these upper classes? This is even more confusing than fish knives were in the Fifties. Surely the Royals must be top of the heap? Not at all, says social forecaster Peter York, co-author with Ann Barr of the Sloane Ranger Handbook. 'If you count your roots back to 1400, the Royal Family seems rather recent. People say they are vulgar because they behave in a very middle-class way and they are German.'
Alan Clark thinks the Queen is 'all right' and Diana is 'a goddess' but says it is difficult to dredge up 'pejoratives strong enough' to describe the 'vulgarity, brutishness and maladroitness' of the 'utterly contemptible' rest.
The social status of Clark himself appears to be a rather vexed question. Son of the late Lord Clark, art historian and author of Civilisation, he inherited a family fortune based on the thread industry, plus Saltwood Castle in Kent, and an estate in Scotland; Mrs Clark is the daughter of a lieutenant-colonel. 'The Clark family made their money in the 19th century,' says Peter York. 'Many of our grandest families did the same. Most people would regard the upper classes as one big group but there are nuances and divisions, a whole series of impenetrable differences based on money, privilege, ancestry that are absolutely opaque to outsiders - exquisitely fine distinctions.'
This perhaps explains how Daily Telegraph leader writers last week came to describe Alan Clark as a 'putative toff, whose father bought his own castle'.
'It is confusing,' York adds kindly. 'Most nobs look the same to outsiders.'
There is a hint of a raised eyebrow about this week's media circus. 'Alan Clark going into print in this way is . . . untypical behaviour for this class,' says York - a view shared by Bill the railwayman, Saltwood's oldest inhabitant, who says: 'Having affairs is one thing, but publicising them is not the sort of thing gentlemen should do.'
Sir Peregrine Worsthorne believes the social balance has shifted away from snobbery. 'It irritates me when people call me a snob - it isn't true. The word is very often used stupidly. It's much less widespread than it used to be. Nobody is enormously impressed by a title any more. Very large quantities of money create a bigger impact than being a duke.'
Property and titles can still play their part, however. 'Treating the owners of Blenheim or Chatsworth differently to someone who owns a suburban villa isn't snobbery, it's simply normal behaviour. The upper classes played such a huge part in shaping the country that the momentum of that prestige lingers on.
'Snobbery disappeared more rapidly under Thatcher than ever before - capitalism rather than socialism gets rid of snobbery, because it brings in the power of money. The media have pre-empted a lot of the glamour that made the upper classes attractive. People are overawed by media personalities - Jeremy Paxman, for example.
'I don't think Alan Clark is a snob. He has an aristocratic disregard for bourgeois virtues like thrift and caution. He has a buccaneering, daredevil insouciance which is very rare these days. He's a cavalier, and they are always more admired than the roundheads. '
Dr Michael Argyle, a social psychologist at Oxford University, author of The Psychology of Social Class, thinks, 'Our society is actually very mobile. One third of any class will move up or down during their lifetime - and more will move up than down. We are also egalitarian - 40 per cent of people's friends are from classes other than their own. Even the top professional class is relatively easy to get into.' Hyacinth Bucket, take heart - but only up to a point. 'There is a more rarefied group, right at the top, the kind of people who own castles, which is almost a closed society,' according to Dr Argyle.
But climbers may still experience cruel snubs on the way up. 'There was real, old-fashioned social snobbery at two of the schools I went to,' says Amanda, 26, a journalist and former pupil of a 'very social, un-academic, girlie school.'
'There was a girl who came from Swindon, her mother was a doctor - very rare to have a working mother - and she had been to a secondary modern. This was the source of much hilarity - as was her regional accent, the only one in the whole school. People used to shout Swin-dern every time she walked into a room, and one very grand girl coined the joke that she was the House of Commons while the rest of us were the House of Lords.
'They were affronted by her because they had been sent to that school to meet nice people, and Swin-dern wasn't nice. Actually she was stoic. At my prep school I was told I was common because I called my mother Mum, not Mummy. And people whose parents had common cars - for a time mine had an orange Datsun - were in trouble on sports day.'
Snobbery crops up everywhere; last week cricketer Imran Khan was complaining that his critics are lacking in 'class and upbringing'. It can also rebound in unexpected directions. 'The country is in the state it is today because John Major didn't go to public school. I might even might vote Labour as Tony Blair is a public school boy,' snorted the Honourable Robin, an affronted former true-blue Tory.
But wherever an exaggerated sense of upper-crustery may lead, it means never having to say you're sorry. All aristocrats, says Nancy Mitford in Noblesse Oblige, are 'impervious to a sense of shame. Shame is a bourgeois notion.'