After last weekend, I’m determined that this time Mum and I will do something useful together.

A perfect opportunity arose: the granddaughter’s ball dress. It’s been tried on, measured and pinned. We’ve had expert advice. “Blind hemming,” says my fashion school friend. “If you use the machine on that, it won't look good.”

I know just the person.

By 11 a.m., I’m in Mum’s room. She's lying fully clothed on her bed. I tell her the plan, and she’s up. We talk about it all the way to my place.

"And when is this ball?" She inquires.

"Tonight."

"Goodness, we’d better get going!"

Back at my house, Mum’s straight into it. “Herringbone or feather stitch?”

I have no idea.

“I’ll just do something very plain,” says Mum.

It’s so plain I can't see it: tiny, neat stitches underneath with not a trace of thread on the outside. Mum’s happy as a clam, head down stitching away.

I suggest lunch, but she politely declines. “Not ‘til I’m half way.”

An hour later, and she’s gone right round. "Finito!" exclaims Mum. Then she agrees it could possibly be time for lunch.

Mum admires the dress. “She’s going to look smashing in that!”

Indeed.

Later, as I’m driving her back to the rest home, Mum says, “I wish I could be more helpful." So I tell her about the hemming, the perfect job she did and how it’s practically a lost art. No one knows how to do that stuff anymore.

It’s not that she doesn't believe me, it’s just that she doesn't seem to remember. Then she thinks for a minute.

"I’m not that good," Mum says.

"Oh, no?"

"If I was that good, I’d have made sure you learned how to do a decent hem."