First impressions can be very deceptive.

What, for instance, would you make of a furtive looking woman trying to pretend that her hand isn't really stuck inside a post box?

She's trying to steal the mail? Wrong.

Something unpleasant lurking inside the box has caught her by the wrist and intends to chew off her fingers? Wrong (I hope!).

She's trying to retrieve a letter? Right.

Why is she trying to retrieve a letter?

Is it packed with passionate declarations of love she now regrets writing?

Is it full of unfounded gossip and wild rumours she was intent on spreading but now fears may have serious repercussions on her own social standing?

No, and no again. She is trying to retrieve a letter addressed to her elderly aunt which is minus the required postage stamps.

"What are you doing?" says The Mother who has been inside the post office posting a parcel to the same elderly aunt, her sister.

I consider telling her that some unseen monster lurking in the post box really has got my hand between its teeth but seeing the annoyance on her face decide to tell the truth instead.

"I've forgotten to put any stamps on the letter," I say. It is not the first time this has happened but The Mother doesn't know that.

"Is your hand stuck?" The Mother asks.

"Just a bit," I reply. I have broad hands (and feet to match) while hers are small and slender.

"Well, we can't call the fire brigade to release you that's for sure," she says.

"You could try greasing it with margarine," says an elderly man who has been patiently waiting to post his own letters.

"It's all right, I'll just try wriggling it about a bit, that should get it out," I tell him, wondering what an earth any passers by would make of these snippets of conversation.

On its release my hand looks slightly swollen and the knuckles are grazed.

I get no sympathy from The Mother. "If I had done that you would have said I was completely dotty," she says.

She is right of course. Being elderly I'm afraid I expect her to be slightly confused and forgetful, forgetting to put stamps on letters for example.

"Got your purse, bus pass, glasses, cigarettes?" I ask before we set off shopping.

Who am I kidding? The truth is she is still as sharp as a tack while I have become increasingly absent minded.

Sometimes when I glance down I expect to see dead brain cells scattered across my shoulders like dandruff.

I leave the bathwater running into the overflow while I go to answer the phone and sometimes I forget to flush the lavatory.

I let saucepans burn dry and my toast looks like charcoal. I get milk from the fridge and forget to shut the door and I rarely remember to put detergent in the washing machine.

I've bought the same magazine twice in one week and sometimes find myself reading a library book which seems vaguely familiar because I first read it - and forgot it - six months previously.

I've missed doctors' appointments and stood forlornly outside cinemas waiting for friends who were expecting me the following day.

Earlier this year I looked in my wardrobe for a favourite jacket and couldn't find it. The reason? It had been waiting for me at the dry cleaners for several weeks.

Considering I'm so forgetful, you may ask how I come to remember all these incidents?

Simple. There is always someone there to remind me, someone who never, ever forgets ... The Mother. The Mother? Oh, yes, that mother.