I was back in Trafalgar Square again today. The purpose of the visit was to spend my lunch break having a quick look in the National Gallery, but I got distracted by an altercation between a die-hard pigeon-feeder and a disgusted-from-Tunbridge-Wells-type who was trying to stop her.

However, I did manage to find the bits of the National Gallery which I wanted, which were the Canaletto paintings of Venice, the Rembrandts and the Dutch realists – particularly the de Hooch painting The Courtyard of a House in Delft.

As a bonus, I stopped by Holbein’s The Ambassadors as well, but there was a huge crowd listening to a lecture there, so I could not squeeze by to look at the anamorphic skull from the side.

It really is a long time since I went to the National Gallery. I used to make quick visits to it a lot, by using it as cut-through to Leicester Square. I figured that I would go in via the main entrance and come out by the Orange Street (I think) entrance and take a different route each time, stopping to look at different paintings each time. It was a way for someone with a short attention span to get to see more of the place eventually.

Since then I have hardly been back at all. In fact I think I have only been in once since the Sainsbury wing opened 15 years ago. Another example of how you can take your surroundings for granted. It is so hard for those who live or work in London to remember to act like a tourist sometimes. I had forgotten just how many of the world’s best and best-known paintings were in the place: this selection of just 30 works is barely scratching the surface.