You may be familiar with coal holes — the decorative, drain cover-like hatches that stud London's streets, and through which coal was once poured into bunkers below. Artist Simon Turner transfers these wonderful coal hole designs onto decorative bowls. Here, he tells us more.

I've always been fascinated by coal holes. There are hundreds of designs across London.
I've found 28 designs in Stoke Newington alone and there are a few Islington streets that have a wide selection. They date back to the mid 19th century when nearly all homes were heated by coal.

The foundries are all gone but they went to a great effort to design and make what are essentially pieces of street art. You just have to keep your eyes peeled.

Once I've located a good one I will roll out a slab of clay, take it to the location and press it into the coal hole. I sometimes ask permission if it's on a doorstep but many are just in the pavement. I’ve started taking commissions from people who have a favourite nearby. Taking a clay impression is totally harmless and doesn't leave a mark on the headstone so I’m not causing any damage but I do tend to work early in the morning when no one is around to ask me what I'm up to!

The clay impression is left to dry and then fired to give me a mould which I can use multiple times. Also this means the finished bowl is the right way round and not in reverse. Bowls are fired once and then again for a glaze firing.

Before the bowls came the trees and the graves. Bunhill Fields has some great ones including Blake, Bunyan and a memorial to Defoe. Mary Wollstonecraft is down near St Pancras and is a little neglected, and I haven't even tried Highgate yet.

When people see them in the gallery they are surprised as to what they are. I send them down Camden Passage to see if they can spot any. There are quite a few, and Noel Road nearby has some belters.

I am adding more coal hole and grave ceramics all the time — my latest is a grave bowl from a church in Suffolk which has the best 'memento mori' skull and crossbones. And yes, I did ask permission!

If anyone has a favourite coal hole, let me know and I'll come and turn it into a bowl.
Visit Simon's website, follow @simonturnersart on Instagram, and go and say hello in person at The Bakery gallery in Islington, Thursday to Sunday.