I was worried about Sherlock. I mean, I always worry about Sherlock. He's unique, and must be dealt with accordingly, and sometimes I wonder how he ever survived when he lived on his own before Baker Street – not that I think my influence has changed his life in any significant way, but because he seems so ill-adapted to life outside of the great palace that sprawls across his brilliant brain. Society remains indebted to him; he remains entirely unaware of quite what society gets up to when it's not committing crimes. In my time at Baker Street I have cooked and cleaned, bought food and other essential items – as if I lived on my own, to be perfectly honest, and it's manageable. Mrs H has of course been indispensable in keeping Sherlock out of trouble (well, keeping 221B out of trouble: Sherlock will not be tamed).

I am always worried about Sherlock, but never more than the first time I left Baker Street for a couple of days to see my parents – a weekend, nothing more, but it seemed far too long. I wrote in the visit on the calendar – three days, two nights – and Sherlock noticed this later in the day, guessing that I was going to my parents' house, asking me a couple of details, as anyone might; and then Friday arrived and I was just about to go to the tube station when Sherlock stopped me.

'Don't worry about me, John,' he said with a smile and a wink. Then he nodded a second goodbye and I left.

John, how does one cook an egg? SH

It depends on how you like them. Ask Mrs H. JW

She's out. You said eggs were easy. I tried microwaving one but it exploded. SH

Only you would explode an egg! ;) JW

No, the microwave exploded. SH

Oh God. Luckily Sherlock meant that it had made a bang-y noise like a fuse blowing rather than that it had turned into an eggy fireball. And even more luckily, Mrs H returned before Sherlock could do the same to the rest of the kitchen appliances.

Harry dropped in briefly whilst I was with my parents, and asked me how things were going with the eccentric. I grimaced a little but tried to hide it, instead retelling the most exciting cases we had been involved in, never alluding to any aspect of life within the long-suffering walls of 221 Baker Street.

John, what colour is the wallpaper in the bathroom? SH

White, isn't it? Why? JW

Damn. I was hoping you wouldn't remember. SH

When I returned home I found that the walls were a rather interesting marbled orange effect due to some chemical experiment that Sherlock had attempted in the bathroom sink because Mrs H wouldn't let him use the kitchen sink. (She didn't want him to use the bathroom sink either but there's a lock on the bathroom door.)

On the Saturday evening we went out to see a film. It was a very Watson family thing to do, and I had fond memories of seeing films as a child and getting to eat more sweets in two hours than I was usually allowed in a week. The difference here was that I had lost my childhood fondness for E-numbers, and that the film had much more violence in. Not as much as my real life had though. The protagonist looked a little like Sherlock, but had a lot more common sense.

Not that Sherlock is stupid. Of course he isn't. He just has more uncommon sense. He can deduce where you have been from the soil on your shoes but he can't work out which side of an iron you're supposed to use without touching it to see if it's hot.

John, I've burnt my finger on the iron again. SH

Point proved.

Sherlock is prone to missing meals, and can sometimes endure for days without eating and sometimes drinking. He claims that his mind isn't affected by it but I can see that the grumpiness that afflicts him after such fasts is more due to dehydration than the boredom of the lull between cases. I had to send him a message every mealtime to make sure he ate. He only replied to some of them, but when I returned I found an almost-adequate pile of unwashed plates in the sink, and instead of complaining at him for not washing up I praised him for remembering to eat.

It was only when I got round to washing up for him that I realised that whatever had been on some of these plates definitely hadn't been food.

I went to the supermarket today. SH

Oh good. How was it? JW

It was horrible. SH

Well, at least you went. JW

I didn't end up buying anything. I got arrested before I had chance to pay. SH

...Why? JW

The self-checkout was annoying me so I shot it. SH

I returned in the evening on Sunday to find the house in the state of minor chaos I have outlined above. The living-room had survived, but it was covered with papers that Sherlock claimed were organised alphabetically: A on my chair, B on the window ledge, C in the middle of the rug, etc, all the way to Z behind the door, a curious stack containing a surprising number of articles about Zebras, Zoology and Zips. A knife was thrust into a pile of important-looking documents on the table, and also the table. I found the kitchen in something of a state, and the bathroom... well, you know about that already. It was a couple of days before we had cleared everything up and bought a new microwave – well, before Mrs Hudson and I had, anyway, as Sherlock was busy on another case, leaning back in his armchair perched precariously on the H section of his "encyclopaedia".

It was the first and last time I left Sherlock alone for so long. I found myself wondering which of his bizarre tendencies had led to him being thrown out of the flat he had had before 221B – how he had even survived.

But I did not complain about anything that he had done, because I was his friend, and because I knew a lot about how his mind worked even after such a short time. Dear Sherlock. Nobody understands him, but though it is easy to chastise him, it is much better for both parties if you learn to live alongside him rather than against him.

And at last, on Wednesday evening, all was as calm as it could possibly be. I drew the curtains and came over to sit in my armchair, which had been relieved of the articles about Assassinations and Anthropology and Aardvarks (seriously, there was an article about aardvarks), and watched Sherlock as he slowly emerged from one of his "daydreams"; he had on that naïve, almost angelic face that never fails to stop anyone from being angry at him; he looked across at me and smiled; and after a moment he spoke.

'Thank you, John,' he said.