A small ‘incident’ took place yesterday which summed up the personalities of all three of my children perfectly. Here’s what happened.

It was late on Saturday morning – well, 9am, which qualifies as late in our house – when a piercing wail interrupted the tranquil silence.

I, Detective Dad of New Thatcham Yard, quickly arrived at the scene of the crime – the boys’ bedroom – to discover the following:

The crime: One Duplo dog house, destroyed.

The victim: Toby (occupation: Lego Master Builder, aged four).

Lead suspect: Kara (brown hair, brown eyes, medium build, aged nearly two), last seen fleeing the scene with an evil cackle like a toddler version of President Business.

It didn’t take an avid Sherlock fan to deduce what had happened.

Kara is destructive at the best of times and, while she worships Isaac, she is not above winding up Toby at every opportunity, whether it is a sly pinch or a punch, stealing one of his favourite toys or simply going into Hulk-smash mode. She knows exactly what she’s doing too. Does it stop her? No.

By the time I turned up, Isaac was already comforting a tearful Toby, helping him to gather up the pieces that Kara had scattered all over the room and offering to help rebuild the house. Our oldest child is not above winding up his younger brother himself – although words are his chosen weapon, rather than hands and fists – but at times like this he always slips naturally and unselfishly into big brother mode.

In fact, I didn’t need to do very much else. Isaac calmed Toby down – spookily, he uses exactly the same words and tone of voice that Heather does – suggested he rebuilt a new and better house and, job done, wandered off downstairs to give Toby his space and hand him over to me.

Toby and I started experimenting with some alternative designs, and two minutes later Kara reappeared to say sorry to Toby and offer him a cuddle. She knows what the rules of the game are and what she is required to do after every misdemeanour. It won’t stop her from doing the same again a few hours later, of course.

After a few more minutes, Toby was so engrossed in construction that he was happy to be left alone to play in peace. He’s so like me in that sense. All the company he needs is his own ideas and then some material to quietly develop them with.

He’s very different from the other two. Isaac in particular has to have someone to share his activities with and bounce ideas off, and he provides a running commentary for everything he does. Not so Toby, who’s happiest in his own skin and content to play quietly and unobtrusively, to the point that it’s easy to forget that he’s actually there.

So there you have my three kids in a nutshell. The academic, the loner and the anarchist. Case closed.