OK. Don’t panic. I’m in charge. I, Rebecca Brandon (née Bloomwood), am the adult. Not my two-year-old daughter.

Only I’m not sure she realizes this.

‘Minnie, darling, give me the pony.’ I try to sound calm and assured, like Nanny Sue off the telly.

Aargh. I’m holding about a million shopping bags, my face is sweating, and I could really do without this.

It was all going so well. I’ve been round the whole shopping mall and bought all the last little things on my Christmas list. Minnie and I were heading towards Santa’s Grotto, and I only stopped for a moment to look at a dolls’ house. Whereupon Minnie grabbed a toy pony off the display and refused to put it back. And now I’m in the middle of Pony-gate.

A mother in J Brand skinny jeans with an impeccably dressed daughter walks past, giving me the Mummy Once-over, and I flinch. Since I had Minnie, I’ve learned that the Mummy Once-over is even more savage than the Manhattan Once-over. In the Mummy Once-over, they don’t just assess and price your clothes to the nearest penny in one sweeping glance. Oh no. They also take in your child’s clothes, pram brand, nappy bag, snack choice and whether your child is smiling, snotty or screaming.

Which I know is a lot to take in, in a one-second glance, but believe me, mothers are multi-taskers.

Minnie definitely scores top marks for her outfit. (Dress: one-off Danny Kovitz; coat: Rachel Riley; shoes: Baby Dior.) And I’ve got her safely strapped into her toddler reins (Bill Amberg leather, really cool, they were in Vogue). But instead of smiling angelically like the little girl in the photoshoot, she’s straining against them like a bull waiting to dash into the ring. Her eyebrows are knitted in fury, her cheeks are bright pink and she’s drawing breath to shriek again.

‘Minnie.’ I let go of the reins and put my arms round her so that she feels safe and secure, just like Nanny Sue recommends in her book, Taming Your Tricky Toddler. I bought it the other day, to have a flick through. Just out of idle interest. I mean, it’s not that I’m having problems with Minnie or anything. It’s not that she’s difficult. Or ‘out of control and wilful’, like that stupid teacher at the toddler music group said. (What does she know? She can’t even play the triangle properly.)

The thing about Minnie is, she’s … spirited. She has firm opinions about things. Like jeans (she won’t wear them), or carrots (she won’t eat them). And right now her firm opinion is that she should have a toy pony.

‘Minnie darling, I love you very much,’ I say in a gentle, crooning voice, ‘and it would make me very happy if you gave me the pony. That’s right, give it to Mummy …’ I’ve nearly done it. My fingers are closing around the pony’s head …

Ha. Skills. I’ve got it. I can’t help looking around to see if anyone’s observed my expert parenting.

‘Miiiine!’ Minnie wrenches the pony out of my arms and makes a run for it across the shop floor. Shit.

I grab my carrier bags and leg it furiously after Minnie, who has already disappeared into the Action Man section. God, I don’t know why we bother training up all these athletes for the Olympics. We should just field a team of toddlers.

As I catch up with her, I’m panting. I really have to start my post-natal exercises sometime.

‘Give me the pony!’ I try to take it, but she’s gripping it like a limpet.

‘Mine poneee!’ Her dark eyes flash at me with a resolute glint. Sometimes I look at Minnie and she’s so like her father it gives me a jolt.

Speaking of which, where is Luke? We were supposed to be doing Christmas shopping together. As a family. But he disappeared an hour ago, muttering something about a call he had to make, and I haven’t seen him since. He’s probably sitting somewhere having a civilized cappuccino over the newspaper. Typical.

‘Minnie, we’re not buying it,’ I say in my best firm manner. ‘You’ve got lots of toys already and you don’t need a pony.’

A woman with straggly dark hair, grey eyes and toddlers in a twin-buggy shoots me an approving nod. I can’t help giving her the Mummy Once-over myself, and she’s one of those mothers who wears Crocs over nubbly home-made socks. (Why would you do that? Why?)

‘It’s monstrous, isn’t it?’ she says. ‘Those ponies are forty pounds! My kids know better than to even ask,’ she adds, shooting a glance at her two boys, who are slumped silently, thumbs in mouths. ‘Once you give in to them, that’s the beginning of the end. I’ve got mine well trained.’