It has been the first day of summer. I walked from Borough Market, past the Globe Theatre, listening to wavelets lapping in the river, and wondered if these wharves and alleys were familiar to the characters in Wolf Hall. Of course, Shakespeare drank in taverns here. And so did Samuel Pepys. But they came along a bit later.

But I'm sure that Thomas Cromwell did business on the river. Because he had his finger in so many pies.

People were sunning themselves on the small, sandy beach. (I love it that there's a little beach in the middle of London.) But nobody was making elaborate sand sculptures today.

I bought sourdough bread and blue cheese from Neal's Yard (so light and fresh you can taste the grass in it, only of course now I can't remember its name.) I bought chicory and fennel for a salad. And I winced at the price of leafy, Italian lemons. I decided that £1.70 for a single lemon was far too dear for me. Even if it was the most beautiful lemon in London.

Then I bought Italian porchetta on a soft bread roll, and a very large salted caramel ice-cream, and I sat outside Southwark Cathedral in the sunshine and had a picnic on my own.

There is a monument inside the cathedral to a 17th century quack doctor who was famous for miracle pills made from sunbeams. He is reclining on his tomb and he looks as if he's chuckling to himself about all the patients that he's fleeced.

I love the way that London makes the most of a few hours sunshine. There were deckchairs set out on a strip of astroturf outside Foyles bookshop.

Maybe Dr Sunbeam knew what he was doing.