The English obsession with home-improvements is not just about territorial marking, of course. It is also about self-expression in a wider sense: your home is not just your territory, it is your primary expression of your identity. Or at least that is how we like to think of it. Almost all of our DIY-temple sample saw themselves as exercising their creative talents, and other interviews with nestbuilders in furniture shops, department stores and homes confirm that although DIYing may be, for some, merely an economic necessity, we all see the arrangement, furnishing and decorating of our homes as an expression of our unique personal taste and artistic flair.
And it is, but only up to a point. The more closely I researched this question, the more it became clear that the way in which we arrange, furnish and decorate our homes is largely determined by social class. This has little or nothing to do with wealth. Upper-class and upper-middle-class homes tend to be shabby, frayed and unkempt in a way no middle-middle or lower-middle would tolerate, and the homes of the wealthiest working-class nouveaux-riches are full of extremely expensive items that the uppers and upper-middles regard as the height of vulgarity. The brand-new leather sofas and reproduction-antique dining chairs favoured by the middle-middles may cost ten times as much as the equivalent items in the houses of upper-middles, who despise leather and 'repro'.
In the homes of the middle-middles and below, the 'lounge' (as they call it) is likely to have a fitted carpet (among the older working classes, this may be a patterned carpet; among nouveaux-riches, deep-pile). The higher castes prefer bare floorboards, often part-covered with old Persian carpets or rugs. The middle-middle 'lounge' might have a cocktail cabinet, and their dining room a hostess trolley. The contents of lower-middle and some upper-working 'front rooms' will often be obscured by net curtains (useful as a class-indicator, but otherwise something of an annoying obstacle to peeping-tom researchers) but they are likely to be dominated by large television sets and, among the older generations, may boast embroidered or lacy covers on the arms of chairs and carefully displayed 'collections' of small objects (spoons, glass animals, Spanish dolls, figurines) from package holidays or mail-order catalogues.
Younger lower-middles and upper-workings may have less fussy tastes - their 'living rooms' are often uncluttered to the point of dentist's-waiting-room bleakness (perhaps aspiring to, but never approaching, stylish minimalism). They will compensate for this lack of visual interest with an even bigger wide-screen television, which they call the TV or telly and which is always the focal point of the room (and, incidentally, currently shows at least six programmes every week about homes and home-improvement) and a high-tech 'music centre' with big speakers. Many upper-middle homes also have big televisions and stereos, but they are usually hidden in another sitting room, sometimes called the 'back room' or 'family room' (not 'music room': when upper-middles say 'music room', they mean the one with the piano in it, not the stereo).
Coasters (little mats for putting drinks on to stop them damaging the tables) are another useful class-indicator: you are unlikely to find these in upper-middle or upper-class houses, nor will you often see them in lower-working-class homes. Coasters are the preserve of the middle-middle, lower-middle and upper-working classes - or rather, more specifically, those among the upper-workings who aspire to middle-class status.
Matching and Newness Rules
The lower-middle and working-class lavatories, which they call toilets, may have matching coloured loos and basins, which they call bathroom suites, and even matching coloured loo paper. Those of the upper-middles and above will almost always be plain white, although you will sometimes see a wooden loo seat.
At the highest and lowest ends of the scale (upper-middle and above, lower-working and below) you will find old, threadbare and mismatched furniture, while the classes in between favour brand-new 'suites' of matching 'settees' and armchairs, 'sets' of matching dining tables and chairs, and yet more 'suites' of bedroom furniture with matching bedspreads, cushions and curtains. (These carefully co-ordinated furnishings may involve cottagey-chintzy flowers, Conran-Ikea 'simplicity', or television-inspired 'themes' but the principle is the same.) The upper echelons, proud of their eclectic antiques, sneer at matching 'suites'; the lower echelons, ashamed of their ill-assorted cast-offs, aspire to them.
In fact, an English person's social class can be gauged immediately from his or her attitude to expensive brand-new furniture: if you think it is 'posh', you are no higher than middle-middle at best; if you think it is 'naff', you are upper-middle or above. An upper-class Tory MP once sneered at fellow Tory Michael Heseltine by remarking that Heseltine had 'had to buy all his own furniture' - the put-down implication being that only nouveaux have to buy their furniture: genuinely upper-class furniture is inherited.
The Brag-wall Rule
Another helpful class-indicator is the siting of what Americans would call your 'brag wall'. In which room of your house do you display prestigious awards you have won, or photographs of yourself shaking hands with famous people? If you are middle-middle or below, these items will be proudly on show in your sitting room or entrance hall or some other very prominent place. For the upper-middles and above, however, the only acceptable place to exhibit such things is the downstairs loo.
This trick is 'smart' in both senses of the word (posh and clever): visitors are highly likely to use the downstairs loo at some point, and to be impressed by your achievements, but by displaying them in the loo you are making a joke out of them (taking the piss, even) and thus cannot be accused of either boasting or taking yourself too seriously.
The Satellite-dish Rule
From the outside of an English house, even if you are not familiar with the class-semiotics of plants and flowers, which I will come to later, you can make a quick broad-brush class assessment based on the presence (lower class) or absence (higher class) of a satellite dish. This is not an infallible indicator - although many people classify entire neighbourhoods by counting satellite dishes - but a house with a satellite dish can be classified at the lower end of the social scale until proven otherwise by the presence of unequivocal upper-middle or upper-class features.
A satellite dish on a very grand old house in an upper-class area could, however, be a sign of nouveau colonization. But to be sure, you would have to go inside and look for cocktail cabinets, thick carpets, brand-new leather sofas, circular baths and gold taps. If instead you found faded colours, priceless but threadbare oriental rugs, shabby damask sofas covered in dog hair and cracked wooden loo seats, you would revise the occupants' social class upwards, and assume that they had some suitable reason for watching satellite television - work in broadcasting or journalism, perhaps (check for BAFTAs in the downstairs loo) or an eccentric passion for basketball or sit-coms or some other aspect of popular culture.
The Eccentricity Clause
Which brings me to a further complicating factor: taste is often judged, in social terms, not by the deed but by the doer. If someone is securely established as a member of a particular class, his or her house may feature a number of exceptions to the rules I have mentioned without any danger of reclassification downwards or upwards. I read somewhere recently that Princess Anne's house, Gatcombe Park, is cluttered with displays of every gift she has ever received, including the sort of tacky national dolls and cheap African carvings normally only found in working-class 'front rooms'. Such signs of plebeian tastes among the upper classes or even long-established upper-middles are generally regarded as harmless eccentricities.
And it works the other way round as well. I had a friend of impeccable working-class credentials - a school cleaner, living on a run-down council estate - who had a passion for the upper-class equestrian sport of eventing (also known as Horse Trials, and also, incidentally, favoured by Princess Anne). She kept a horse (free in return for mucking-out) at a nearby riding school, and her council-house kitchen was festooned with rosettes and photographs of herself competing in local hunter-trials and one-day events. Her working-class friends and neighbours accepted her 'posh' horsey doings and decorations as an innocuous quirk, a somewhat eccentric hobby which in no way affected her status as their social equal.
This 'eccentricity clause' seems to be most reliably effective at the top and bottom ends of the social scale. The middle-middle, lower-middle, upper-working and even upper-middle zones are more vulnerable to re-classification on the grounds of perceived deviation from the class norm. Here, a single lapse in home-decorating taste may be forgiven or disregarded, but two or more could be damaging. Even among the less vulnerable, it is safest to choose your eccentricity from a class at the opposite end of the scale, rather than from the one immediately adjacent to your own. An upper-middle showing evidence of middle-middle tastes, for example, is much more likely to be suspected and downgraded than an upper-middle with a penchant for an unmistakably proletarian item of furniture or decoration.
In borderline cases, well-intentioned gifts can pose a problem for the class-conscious English. I was once given some very pretty wooden coasters, and not having any tables worth protecting from drink-stains - nor, I must admit, wishing to be suspected of the bourgeois instinct to do so - I use them to prop open my dodgy windows. I could get the broken sashes mended instead, of course, but then what would I do with the coasters? Being English can be quite tricky sometimes.