Unwanted Walter is what happens when you take all your children into a pet shop, slightly hungover and sleep deprived (us, not the children).

London - Rule Number One of parenting. Never go into a pet shop with your children (or anyone’s children). Actually, I suggest that for the duration of parenthood you should avoid a pet shop with anyone under the age of 25 at all costs.

Don’t even walk past one with your offspring. Avert your eyes, cross the road.

Because buying a pet, like weighing yourself on the first Monday after Christmas, is something you must do alone.

How on earth we managed to get through a decade of parenting without stepping over the threshold of an Animal Magic, Petcetera or Paws ’n’ Claws is beyond me.

Friends didn’t believe us, but we stayed strong. Until Gracie-in-the-middle’s tenth birthday last week.

My daughter’s desperation for something of her own to look after and love was becoming uncomfortable. The continual pleading was disarming and non-stop. She talked of nothing else. It was a relentless campaign unlike any others before it.

Then one night as I tucked her into bed she softly murmured: ‘Just one fish.’

And I crumbled. She looked so sad, her little pale face all miserable as she drifted off.

And I couldn’t help but admire her dogged persistence: even in dreamland she remembered her mission (I’m sending her CV to Facebook boss Sheryl Sandberg pronto).

So ‘Gracie challenges’ were set; many sticker reward boards were speedily completed. Her room was show-home tidy, even inside the cupboards and under the bed.

Homework was done early, books read all the way to the end. Sibling rivalries were halted. I think she may even have gone as far as eating a Brussels sprout if I’d asked.

So we gave in. She could have one goldfish. ‘One goldfish,’ I repeated loudly in the car park of Pets At Home as all four of them bounced towards the sliding doors with the enthusiasm of orphans headed to Disneyland.

An hour later I had a tank with no fish in it and Unwanted Walter, a hamster the size of an earring, on my lap.

There are 24 million pets in this country (double the number of pensioners, apparently) and we’ve got one no one else wanted.

Unwanted Walter is what happens when you take all your children into a pet shop, slightly hungover and sleep deprived (us, not the children).

If I’d been a Lone Ranger on the birthday fish mission I’d have been able to resist ‘the wall of rejected pets’, but four sets of teary eyes dissolved my resolve on the ‘no rodents’ clause in my parenting contract.

For the wall of unloved pets is one of the saddest places in childhood. It even brought a tear to my eye and that hasn’t happened since the baby elephant died in front of its mom on David Attenborough’s Africa series.

There the furry little fellas sit with their ‘loser’ CVs written up beside their cages, detailing why they are unloveable.

It said Unwanted Walter, the dwarf hamster, had been brought back twice, once because he’d been bullied in the cage by his siblings (code for fighting).

He’d been on the wall for a record amount of time - he was thus the least appealing of the lot. ‘Oh my God, that is terrible,’ the kids wailed, no doubt imagining themselves in that position, as all children generally think about is themselves.

We’d just been told that we couldn’t buy a fish until we’d set up a tank at home and had the water tested after a week (who knew the world’s most boring pet would need so much care?). So for a moment it looked as if we could walk away from the pet shop animal-free.

But then they spotted ‘the wall’.

They said they’d give up their pocket money for a month to buy hamster accessories and quickly outlined a surprisingly well thought through cage-cleaning rota.

But I was already smitten with Walter, a tiny tearaway with a big personality. I liked the way he hurtled around the cage manically. It reminded me of something.

‘We’ll take the one no one wants,’ I said to everyone’s surprise and gratitude.

Everyone loves Unwanted Walter, despite his tendency to nip.

‘He’s an attack hamster,’ my seven-year-old son tells me as Walter hangs off his little finger with a determined glint in his eye.

Anyway, it’s a good job we got Walter because Dave, the fish we got a week later, died 24 hours after putting him in the tank. - Daily Mail

* LORRAINE CANDY is editor-in-chief of Elle.