New parents hear so much about ‘the terrible twos’ that it’s very easy to be lulled into a false sense of security. You sit there with your incredibly well-behaved baby and think with smug complacency that you have two years of parenting practice before having to face the horrors of unstoppable tantrums and a wilful refusal to behave.

And then you discover that’s a load of total crap.

For the past couple of months Izzie’s known what ‘No’ means, but played a little game called ‘how far can I push it?’ That’s normal and natural and the sign of a confident baby with an active mind and growing sense of independence, and I welcomed it.

The door to the hallway, for example –  it doesn’t close properly, and Izzie’s aware that if she rolls the doorstop out of the way, slips her fingers into the crack and pulls, she can wrench it open and escape into the magical and dangerous world that is the rest of the house. So whenever she tries this, I give her a stern ‘No,’ with a pointed finger and a glare.

In the past, she looked back, her hands dropping into her lap. Then, slowly, without breaking eye contact, she’d lift her hand and start to stroke the door jamb – ‘not touching it, daddy, see? Quarter of an inch away, but my fingers aren’t in the crack. Not doing anything wrong.’

Same with the plug sockets. ‘I’m just stroking the wall, daddy, millimetres from the plug you told me not to touch. You could barely get a sheet of paper between my fingers and the socket, but I’m not touching it, so you can’t punish me.’

And if she ever did get the door open and I told her ‘No’ a moment too late, she’d hover on the threshold, hold my stare, tentatively ease a toe into the hallway, listen to me tell her ‘No’ again, and then slowly and deliberately shift her whole foot across the line – just to see what she can get away with, just to see how far she can go.

Provocative, sure, but entertainingly so. She was intelligently exploring the limits of my authority and the consequences of her actions; I was showing her where the boundaries are while she pushed against them to see how flexible they might be. Normal and natural. How I miss it.

In the past fortnight, Izzie has learned to clap, developed her first mole (on her forehead), and yesterday cut her first tooth (lower left incisor). And since she’s now so clearly an adult, she thinks she doesn’t have to listen to a word I say anymore.

It doesn’t matter how many times I tell her ‘No’, if she wants to open the hall door she’s damned well going to open it. And if she wants to touch the plug socket, hell, she’ll touch it just to show me that she can. And if she wants to crawl into the magical and dangerous world that is the rest of the house, nobody is going to stop her.

She forgets that I’m bigger and stronger than her and actually can stop her simply by picking her up and moving her somewhere else. But alongside the wilful disobedience comes the other symptom of the terrible twos – the tantrum.

Boy, does Izzie know how to tantrum. You wouldn’t think a ten-month-old could do it, but she’s got it down pat. She can’t even walk yet, but she knows how to stamp her feet. She’s as uncoordinated as the next baby, but she can ball her hands into fists and thrash them about in a temper.

A couple of nights back I was bathing her and she was playing with her plastic stacking pots, one in each hand. She took great delight in filling them with water and throwing it over me, before hitting me in the forehead with them and repeating it. After six or seven goes, I decided that enough was enough and tried to take them off her.

It was as if I had just declared World War III.

Getting the pots off her was no mean feet as she has the grip strength of an Amazon, but once I was done, the angry, screaming, thrashing, leg-kicking, arm-flailing, fist-waving tear monster sending tsunamis of water out of the tub and over the bathroom floor bore no resemblance to my cute little well-behaved daughter. It was like being caged with a wild animal with a toothache.

This stroppy self-righteousness has spread to all areas of her daily life. Don’t get me wrong, she’s a very good baby, hardly ever cries, and is a delight to be around most of the time. But she’s decided she can do what she wants, when she wants, and woe betide anybody who tries to stop her.

Terrible twos? If only they’d wait that long!