'Do you remember Mummy getting ready to go out when we were little?' I ask my sister as we share a quick cocktail in Claridges in the lost half hour between leaving the office and going home - the unreliability of the Central Line providing an excuse for sneaking in a drink and a gossip before dashing back for the children's bath-time. 'She used to lie on her bed for ages under a Charles of the Ritz face-masque before putting on her party make-up - Max Factor Crème Puff and the Charles of the Ritz cream eyeshadow that came in little pots of peacock blue and bronzy gold - and her mascara was the block kind you had to spit into.'
My sister gives a moue of disgust, evidently wondering how women escaped conjunctivitis in the early seventies if that was the sort of primitive cosmetic on offer.
'I don't remember the makeup,' she says, beadily watching me hoover up the last of the olives, nuts and cheese-straw-ish things, 'But I do remember her evening bag: it was all shiny black sequins and there was never anything in it other than spilt face powder. And she had a long velvet skirt from Jollys of Bath worn with a white frilly shirt and patent shoes with buckles and a chunky square heel, very this season Vuitton actually.'
'I loved that outfit - it was what she always wore to go out.'
'She must have had others: She was very glamorous in those days,' says my sister, 'She can't only have had one party look.'
'No, no,' I say airily, 'in the 1970's there were virtually no shops, so it was hard to get anything new, and even if you could, you were basically expected to wear the same thing to everything, or get a reputation for hopeless extravagance, spending all your husband's money.'
'What rubbish,' says my sister with some justification, despite being not quite three in the days of the sequinned evening bag, 'You could get all the latest fashions from Jollys of Bath in 1973. And anyway, there was definitely a dress with big bell sleeves and a swishy skirt that went all the way to the floor.'
'Like Princess Anne's wedding dress, but floral?' I ask, and my sister nods. 'I think that came later, for dinner parties at home. You know, when everyone turned into Margot in The Good Life and wore false nails and carmen-rollered their hair and tripped over their long dresses.'
'I liked being on peanut and crisp passing duty. Don't you think it's weird how much proper booze people drank before dinner in those days? It was all sherry, or whisky or warm gin and tonic – people must have been plastered before they sat down to eat.’
‘They’d sober up during dinner,’ I offer, ‘There was never more than two bottles of wine – some kind of German number for the starter and the fish, and a claret with whatever was in the Hostess Trolley.'
'But then they'd get stuck into the Cointreau or brandy or port after the cheese. And drive home.' Says my sister with thundering disapproval. 'It's a miracle no one got killed.'
The conversation diverts down a health and safety track, taking in Jimmy Saville's 'Clunk Click Every Trip' and the road safety squirrels - the Tufty Club? - before we realise the time and hurriedly pay the bill.
And on the tube home, I find myself thinking about this Saturday's scheduled supper party - no starched linen napkins coaxed into waterlily shapes chez Trefusis, or slavishly followed recipes involving things flambeed in brandy and doused in cream. Nor will women don evening dresses after an afternoon relaxing with a face-pack - dressing for dinner in West London means swapping Converse for heels after frantically wrangling the spawn into bed before the baby-sitter arrives. Smokers will volunteer to light up in the garden, rather than fug the dining room with fag smoke and bibulous guests will take themselves off home via Hailo or Anderson Lee.
Home Entertaining in 2013 is a far cry from what was de rigeur in the years between Ziggy Stardust and The Three Day Week. Nevertheless, some things will never change: the Infant Trefusii will be co-opted into politely handing round the olives, Kettle chips and crudités before being sent to bed, where, like my sister and I nearly forty years earlier, they'll watch the evening unfold from a vantage point at the top of the stairs.
First published on harpersbazaar.co.uk
For my latest Harper's Bazaar post, on beauty, botox and de-ageing, click here