It’s a friend’s birthday today, and I’m going to drop off a cookery book featuring vegetable dishes to her, on my way to work.

It’s not a vegetarian cookery book, quite, but it assumes that most meals you make can be based around stuff you’ve harvested from your garden or allotment, rather than stuff whose collective nouns are flocks or shoals.

That’s a good present, says my husband, whose idea of utopia is a house that consists of a massive kitchen, a music studio, a darkroom, a home cinema, possibly a bedroom if there’s room, and a large garden filled entirely with fully functioning vegetables.

And it is indeed a laudable gift. It encourages its readers to eat what’s in season, and buy stuff that’s been grown locally if they haven’t been able to raise it themselves.

You can’t argue with that. Well, not completely, anyway. We have ourselves dipped our toes into the low carbon footprint water, after all. As I write, I am within ten yards of peas and beans which are struggling against the blackfly and greenfly and slugs and snails that have a long-term lease on our garden, and if we’re really lucky a proportion of them will eventually emerge triumphant, to wait patiently until we arrive with our trusty little scissors and colander to harvest them.

However, self sufficiency in the suburban garden isn’t all it seems.

Have you ever wondered, for example, how Felicity Kendal has managed to keep her fab figure well into her mid 60s? How she went on to win Rear of the Year?

Obvious, when you think about it. It’s because when she was in The Good Life, she and Tom could barely grow enough to keep body and soul together. It wasn’t design – she just never got the chance to consume enough calories or saturated fat to lay down a future midriff bulge or saggy bum.

Despite the calls from celebrity chefs to the contrary, I tell my husband, we’d actually have real trouble managing on the fruits of our labours – even if we started calling the snails escargots.

We’d almost certainly spend half the week digging and hoeing, and the other half eating carrots and stuff, just to keep our energy levels up. And even if we occasionally swapped our garden-grown organic mange touts for some spare ribs from a ewe reared by another small-holding up the road, we’d soon find the diet quite tedious. Deathly in fact.

If we were really, honestly going to live on what we’d produced or swap it for goods produced within, say, ten miles of where we live, imagine what that would mean.

No more fish, except for trout or minnows. No tuna or prawns or laverbread. (No, I’m not that keen on laverbread either, but if I could never eat another piece of seaweed again, I would lust after it until my dying day. That’s the sort of weak individual I am.) No whisky. No lime in gin and tonic. No olives. No point in carrying on, frankly.

And then there’s the other side of growing your own – the gluts. I know a bit about gluts. They’re one of the outcomes of inefficient slugs.

I’d be perfectly happy just managing on what we could produce, says my husband. Anyway, wish her a happy birthday from me.

He turns to the fruit bowl.

We’re not out of bananas again, are we? he asks.