ON Sunday, because it's that time of year, we ploughed the fields and scattered and sang the song of harvest home, even us townies with, at best, a vegetable garden.

There was also a marrow, of course, there always is a marrow. It's really the marrow's only purpose in life, to sit in its full pride by the pulpit or on the altar steps at harvest festival.

It was also the only item not wrapped in clingfilm among boxes and baskets neatly made up for later distribution. No longer do the fruit and vegetables roll unchecked in their containers, they stay put and make life so much easier for Monday's givers out of harvest gifts.

What did we do before we had clingfilm? No wonder New Zealanders call it glad wrap, it's such a welcome addition to kitchen life. No lid for a bowl of leftovers - slap some film over the top, nothing will slop out. Half a melon to store - roll it in film and the cut side stays fresh and the whole package stays dry on the outside. Sandwiches to keep fresh for the next day's bait - wrap them in film.

OK, sometimes it clings too firmly to itself before we can get it sorted out but that clingability is what makes it such an ideal wrapper and sealer.

The expression "best thing since sliced bread" came to mind, bringing with it another thought. With what, I wondered, did people compare new inventions in the days when bread came from the local baker's in unwrapped, fresh-from-the-oven loaves?

Best thing since custard powder, maybe, Alfred Bird having relieved cooks of the need to stir eggs and milk over hot water for a very long time to make the proper stuff.

Then I realised where my wandering mind was coming from (as I remarked here recently, housework is a great aid to thinking).

I'd been reading a web log - a sort of on-line diary - containing a comment on a Thai meal and I'd been amused to see that the writer claimed sticky rice did indeed "do what exactly what it says on the tin". That was followed by the question: "How did we express that concept before the Ronseal adverts?"

A very good point.

In spite of using the phrase myself to describe anything that does, or is, exactly what it claims to do, or be, even when it's never been anywhere near a tin in its existence, I couldn't remember.

What did we say? It works? It's effective? It lives up to its claims? Maybe just a simple: "It's OK."

Certainly nothing as neat, or as expressive, as the phrase given to us by some unknown advertising copywriter who'll never make it into the dictionary of quotations.

It's also a phrase to be borne in mind, as this is not only the season of harvest festivals but also of mists and party conferences, by politicians of every colour, and any shade of that colour, at every level from local government to cabinet, real or shadow.

It does what it says on the tin.

The only guide we have to voting for these people is what they say on their tins.

If only they were as reliable as wood preservatives