I started this blog four years ago with an account of a visit I made to see the buried river Fleet far beneath the pavements of Clerkenwell. A lot has happened in the time since but I’ve remained fascinated by the city – both above and below ground. Here is a picture of the mouth of the river Effra which rises below St Marks church in Brixton and exits into the Thames on either side of Vauxhall bridge. It was taken at low tide when you can also see the mouth of the river Tyburn opposite and that of the river Westbourne farther up stream. There are various other out-falls along the northern bank reminding us that Westminster was once an island. The mouth of the Fleet is very difficult to see but it can be glimpsed from a westbound boat under Blackfriars bridge at low tide. The definitive work on the subject is Nicholas Barton’s ‘The Lost Rivers of London’ and the incredible and intrepid guys at sub-urban have photographed many of the most dramatic underground waterways.

A friend asked me the other day what I would do if I were to be elected Mayor. I had no hesitation in telling her I would cancel the 2012 Olympics (does anyone really want them?) and spend the money on alienating a load of property owners by opening up the rivers again. Oh yes and by making the city vegetarian and it obligatory for everyone who lives here to record their dreams everyday. Ok, so my friend was a wild goose on the Thames foreshore but personally I think this would have a very remarkable and positive effect on us all.

I have been seeing Valentine again. Like Philemon, he has seemed at times to be a somewhat imaginary friend but nevertheless, like the rivers, constant.

To all friends – real or imagined – who have read this blog and listened, watched or commented over the years, much appreciation.

Here’s to another four..