When I went to tuck Harry in the other day, it suddenly struck me how much he has changed in the last few months. There he was, stretched out, filling his cot, looking like a little boy, not the baby of eight or nine months ago.

Because he was fast asleep, I was able to stand and study him and I found myself – not for the first time – feeling very humble about how nature works.

But while I sometimes get misty-eyed about things, Harry has no such concerns. He’s a bundle of energy from the moment he wakes up to the moment he goes to bed – minus his couple of increasingly brief naps during the day.

However, I have noticed that his concentration span is starting to increase, and he’s playing with his toys properly now. For example, a few months ago his little wooden Thomas the Tank Engine train set was used primarily as a weapon; now he will lie down next to the track and gently push the trains around it. Although this doesn’t last long, it is fascinating to watch how he is changing.

Of course, he still likes playing with things he shouldn’t, and his latest obsession is my desktop computer. He likes to sit in the chair, playing with the mouse and tapping away at the keyboard. It’s a comical sight, although it has resulted in the computer becoming increasingly temperamental in recent weeks.

Then there’s the vacuum cleaner. Harry still gets worryingly excited whenever he spots it, shouting ‘Hoover’ as loudly as possible, clapping his hands and hopping from one foot to the other.

Sometimes he will follow me around the house with his own toy vacuum cleaner; at other times, he grabs a duster and the polish does his best to help with the cleaning. I just hope he remembers all this in five years time when we want him to tidy his room.