I think it started when I was a schoolboy while staying with relatives for half term (parents abroad, you know the sort of thing). Searching about for something to eat between rather spartan meals and whilst my aunt and uncle were out, I came across in their vast pantry, a tin whose weight suggested that its contents might be just what I was looking for. I can still see it today; what was once perhaps a sponge cake was now a fragile, spectral froth of luminous green shrouded in silvery mist and sitting in a moat of black ooze. I replaced the lid, put back the tin on its shelf and stole away.

It's not an obsession, more an occasional amusement but, ever since, whenever I've had access to people's kitchen cupboards (pantries are less common nowadays) I've made a mental note of the 'Best Before' dates of two items in particular: Marmite and Angostura Bitters. And, I think we have a record. I happened to slip away for a couple of days over Christmas and during the course of one breakfast, noticed a greyish and slightly blunt taste to my Marmite on toast. I inspected the pot and my eye fell on the date ' Best Before 12/95' - 19 years out of date! Yahoo! That's going to take some beating.

My own bottle of Angostura Bitters is a barely-out-of-nappies 10 years past its use-by date and at 45% proof is obviously self-preserving. Additionally, as tonic and bitters (a Pink Gin without the gin) is The Ambassador's Daughter's choice of drink, it's unlikely to stay the current champions distance in any case. My encounters with bottles of Bitters were most commonly in pubs (rifling through a host's drinks arrangements always required a tact, skill and opportunity that the kitchen cupboard inspection didn't require) and more often than not, the date on the top of the bottle was either unreadable or the top remained in the bar staff's hand, thus precluding close examination but, 3 years out-of-date used to be about average. My fall-back, though inaccurate measure of the age of the Bitters became the amount of dust on the shoulder of the bottle and the embarrassment with which it was presented. Gradually, this essential mixer has disappeared from the bar's array which is a shame because, tonic and Bitters is one of the tastiest and most refreshing drinks ever concocted. Try it.

Women's Institute and locally produced preserves. These hapless victims of first our instinctively charitable nature and then our use-by-date paranoia are the cupboard fillers of the country kitchen. If not distributed as Christmas presents (have we got something for old Oojah - she's bound to be there) then they're as good as on Death Row - forgotten; next stop oblivion.

I once had a lodger, Vicks - an excellent cook - she looked after the Sasol Jordan Racing Team for several years. Vicks also, out of season, applied herself to catering in local country houses. I remember on one occasion she'd made a mushroom soup in one of my big pans but which had then, pan and all, mysteriously disappeared.

Four years later, I found it. It was at its best before that.