The convoy set out from Suffolk for Saffron Walden on its way to see our son Mark in his Christmas production of A Christmas Carol.

I had prepared for snow. A spade, blankets and sand were stowed in the boot, just in case.

Have you any idea how many different sorts of sand there are?

When I went to a well-known DIY store on a mission to buy sand, ice-for-the-extrication-from, I was presented with a bewildering choice.

Small aggregate grey sounded too much like a squirrel. Then there was plastering sand, kiln-dried sand, building sand in light grey, red or natural, and sharp sand.

What to do? Sharp sand sounds as if it might cause a puncture. But I didn’t want to be a pink Barbie, fluffy-headed girly woman and sidle up to a burly builder (oh, I don’t know, though).

“Excuse me, but I have only the body of a weak and feeble woman, could you tell me which of these very manly bags of sand would be best for helping ice-bound vehicles?”

“Well, weak and feeble woman, I am a strong and muscular builder, look at my biceps.”

“Gosh, they’re lovely, Mr Builder.”

“What you need, little lady, is this one,” and he picks up an 800kg bulk bag of aggregate with one hand.”

No, I am not a Barbie, I am a free woman. Huh, I can choose sand... now, which colour do I like best?

In the event I plumped for a modish beige. You can’t go wrong with neutrals.

The bag, which I had already punctured, went into a tin bath in the boot of the car. I had left a small but pretty trail of sand across the car park.

It wasn’t until I decided to put down a few spadefuls of sand on our sloping driveway that I realised the sand had the consistency of talcum powder. It was like the sand you get in an egg timer or the sand you that makes fantastic beach sculptures. It didn’t so much melt the snow as decorate it, like icing sugar on a mince pie.

Anyhow, it stayed in the boot. It was handy for ballast or, if stuck in snow, for creating a work of art while you wait for the gritters.

Mark, and his imminent wife Caitlin, you may recall, have a touring theatre company and this evening we were going to see their version of Dickens’ classic tale of Ebenezer Scrooge.

It is their first Christmas show and, although they were snowed off in London a couple of weeks ago – outdoor shows are always a risk in December – it’s been going well. Next thing you know, they’ll no longer be impoverished actors, they will be poor actors.

Pippa (Mark and Caitlin’s good friend) and I were travelling together and arrived in the Essex town about 45 minutes before curtain (had there been a curtain) up.

We discovered there is a Waitrose right in the town centre and, dear reader, I was torn.

The performance began at 7pm but Waitrose was open until 8. An unexplored supermarket is like a poem:

She browsed among the untrodden aisles

Beside the trolley park

A Maid who there was born to shop

In light or gloom or dark.

It’s not a patch on Wordsworth, I know, but there is something extraordinarily pleasing about finding a packet of fresh lemon thyme when you had resigned yourself to using dried herbs in the stuffing.

The Town Hall in Saffron Walden is a splendid timbered building on the market square and it was here we gathered to watch the performance. We laughed; we cried; we joined in with the carols and it made me feel all warm and Christmassy.

Afterwards, my husband and his hungry carload moseyed off to a restaurant while Pippa and I struck out for home.

That cosily festive cosy feeling lasted all the way to my front door... where I realised hadn’t got my key.