You know those books – How to improve your memory in a week etc? It's going to take longer than a week in my case, writes Lynne Mortimer.

My memory is not what it was... and it was never brilliant.

My husband can recite massive chunks of Shakespeare plays – most of Hamlet's soliloquies and virtually the entire Twelfth Night. He knows how to spoil a girl.

When I am in plays I can manage to learn my lines but one day after the show ends, they're all gone. I remember little of Eliza Dolittle except for: 'Come on, Dover, move your bloomin' arse.' This was uttered during the Ascot scene and it remains my most extreme piece of stage swearing.

My husband usually has a better handle on my lines than I do. I like to think it's because my seething brain is so full of fascinating knowledge that something has to give. But, over the last three or four years, I have noticed my memory is a getting a tad dodgy. And my husband is no longer as infallible as, he remembers, he once was.

This became evident a few weeks ago when we went into town to do some shopping. We parked the car and my mobile phone rang. It was Nicola, a neighbour and friend who lives opposite.

'Are you at home?' she asked, Because your front door is wide open.'

'No, we're in town.'

I mouthed to my husband 'front door open'. 'Tell them we don't want any,' he said.

I asked Nicola to slam the door shut for us and went through my little brain training check: Name, date of birth, age, date today, items on shopping list (always a killer).

When we're together, my husband and I have, between us, almost total recall. When apart we have to accept we will be able to access only half the information we need. Worst of all is being unable to remember what I was trying to remember.

I am currently also having an issue with my handbag. Last weekend, I left it at my daughter's house. Then I walked to the railway station to buy a ticket and didn't realise I had left my bag and purse behind until I was in the ticket office. There was also the time I got to the supermarket, discovered I didn't have my bag, drove home, failed to find my bag and then found it had been on the back seat of the car all the time (slightly exonerated by the fact it was a black bag on a black seat).

The most mortifying experience is to be hailed in the supermarket by someone I have known for years but cannot name. It doesn't help too that I am trying to remember three things I left off my shopping list – fabric softener, sour cream, and bananas.

'Hello, Lynne!'

'Hello! How are you?'

(Thinks: does your name begin J? Jane, Janet, Jo, Jess... fabric conditioner)

'I'm fine, thanks. How are Ruth and Mark?

(Thinks: Oh, great. She knows the family... has she got children? Maybe it begins with S. Sam, Sarah, Sue, Sally, sour cream)

'Really good, thanks...' (Thinks: I wonder if she was at Ruth's wedding. Ann, Alice, Amy, bananas) How are your lot?

'Oh, Jonathan's just been made a professor and Henry's been head-hunted by the UN.'

This pleases me more than I can say... and her name is still more than I can say.

Somehow, I burble on and we part, looking forward to the next time we meet. A quarter-of-an-hour later while I'm queuing at for the self-service check-out, I remember her name (Jill). I have some of my best memory-recovery moments in queues because there is nothing much else to do except look in other people's shopping baskets to see what they've got and if I need it.

I get home and realised I don't have fabric conditioner, sour cream or bananas.

• I caused a small crisis in Wymondham, last week. I was due to talk to a group meeting of WIs and Jo had kindly volunteered to pick me up from Norwich Station. But a tragedy on the line at Chelmsford badly affected the trains and I was unable to get there. Happily, Jo was able to contact a potter who agreed to be guest speaker at short notice. I was sad not to be there and I bet they had scones.