Opinion: So grandparents are spoiling their grandchildren, says a new report. Well, er, yes - isn't that what grandparents are there for, says Sharon Griffiths.

Guilty as charged. Grandparents are in the dock again. Too inclined to treat children and overfeed them, says a new report.

So? Amid much finger-wagging, the researchers at the University of Glasgow – and what a joyless lot they must be - say we're making children ill.

What tosh.

Treat? Overfeed? Of course we do! Surely that's part of the grandparents' job description – to make up for all those years of forcing healthy green stuff into the mouths of the grandchildren's parents, rationing biscuits, refusing chips, hiding the sweets and constantly nagging about manners, tidiness, homework and making them eat left-overs…

We've done the front-line parenting, have the scars to prove it, so now grandparents deserve some fun too – especially as most of us are doing a chunk of childcare.

At least we make sure ours get lots of fresh air and exercise so by the time we hand them back they're exhausted and ready for an early night. (Just like us …)

But I think I know the real reason the Glasgow researchers are getting so pompous and picky.

My mother, a harassed full-time working mother, was very strict as a parent. Treats were few, indulgences rare and from an early age I did lots of jobs around the house.

But as a granny she was totally transformed. She always arrived weighed down with home-made cakes, pies, puddings, bags of sweets. Whatever the boys asked for 'Oh let them have it…' she'd say, letting them watch endless TV and go to bed when they liked and drink fizzy pop by the bucketful. I watched in astonishment – and indignation.

She played endless games with them, refused to hear a word of criticism and apart from an insistence on good manners and clean hands let them do much as they liked.

Needless to say, they loved her to bits, there was a real bond. She was always on their side.

My husband is similarly transformed. A workaholic journalist hardly ever at home, now he's semi-retired – which would be full-time work by anyone else's standards - he has time to spend hours lying on the floor carefully sorting Frozen pictures with the grand-daughters or building train sets while sharing a bag of chocolate buttons. Our sons are stunned.

But it's not sweets or treats that matter most. The luxury that grandparents can give children is their time. As more parents work longer hours from the time children are very young, then they want to make up for lost time with the next lot down. If that includes a treat or two, well why not?

I wouldn't mind a bet that those researchers have all got children who are being looked after by indulgent grannies - and they're just plain jealous. Or they're indignant too, as Granny cheerfully overturns all the rules by which she made them grow up.

No, it's not fair. But did we ever tell them life was fair?

Anyway, I'm off to stock up on sticker books and Haribos. And chocolate Advent Calendars of course.

Whatever those researchers think, a gran has to do what a gran has to do.