L ook Nanny, shark, shark!” And at first we smiled because you do, don’t you? A little curly haired moppet, no older than five, out with her grandmother, at the London Aquarium, on a Sunday, staring into a tank the size of the Kassam Stadium, as a hammerhead went sailing by.

But too much of a good thing can, in certain extreme circumstances, quickly become a living hell.

Now don’t get me wrong, I don’t – nor did I – blame the little tyke, even when she: l Banged on the side of the glass to attract the shy and timid giant turtle (which, with counselling, could be out of its shell again by Christmas) l Squealed, over and over, that she liked the ‘fisheees’.

l Ran constantly (0-60 in three seconds) into everyone’s legs, with all the weight of a small wrecking ball from Mothercare.

l Sucked on the glass of at least six displays, leaving her own drooly, aquatic watermark.

l Splashed more water out of the rays’ tank than was in it to begin with.

l Shrieked constantly during every presentation by aquarium staff (one was at the piranha tank and yes, the thought DID cross my mind...).

Thankfully, I was adult enough to appreciate it wasn’t her fault, but that of her grandma who, in a court of Human Rights, would be found terribly guilty of crimes against humanity.

And you know why? Because during this whole two-hour ordeal, she did nothing but encourage her little ‘dahling’.

“Oooh yes, a S-H-A-R-K. Yes, that’s right Lucrecia (or whatever her name was), give him a knock and shout ‘Hello Mr Sharky’”.

Or (and I hope you’re sitting comfortably): “Now remember dahling that little song Gramps and I taught you? ‘Hey Mr Fish, you’re quite a dish, why do you wave your fins so?’”

A little ditty then so oft repeated that – according to my girlfriend – I screamed it in my sleep.

But hey, that was London, and this woman in her gold lame ballet flats looked like the kind of 70+ diva who’d turn her nose up at Mayfair. Surely in Oxford, such pushy, reptilian ‘aren’t my grandchildren simply divine?’ grandmas would be constrained by a curfew or restraining order?

But how wrong I was! In Borders on Magdalen Street, just a few days later, I experienced the same kind of in-yer-face grandma-ing that had made that Mafia line about ‘swimming with the fishes’ seem so appropriate last weekend.

She was loud, leathery, and certainly more aggressive. Her granddaughter lacked only the rhino hide. And between them, the two pushed, bullied and hollered their way through every picturebook.

Why-oh-why dear God can’t grandmas be like they used to be? You know, old, simple, blue-rinsed and timid? Handy with a cuppa, a graceful smile, and a £1 coin to ‘buy yourself some sweets’.

Don’t these 21st century grannies have any shame?