We reproduce the picture on the right at the risk of causing one of our readers a heart attack. The picture was used in the November issue to illustrate Barry Hunt’s excellent article on the use of natural slate as a building material.

We have to admit it was not a photograph supplied by Barry but a library picture of the market place in Caernarfon sourced by NSS. The aim was to demonstrate that slate makes an ideal material for a lot more construction applications than just roofing.

But the picture sent reader Mike Clarke “incandescent with rage” at “what I believe to be the worst natural stone pavement I have ever seen”.

Mike is a Chartered Civil & Highway Engineer who was responsible for, among a great many other projects, the Caithness stone paving used on the British 9/11 Memorial Garden in New York.

He wrote to us listing the issues he has with what he can see in the photograph (although he says he has not been there in person). He contends that the paving could not comply with British and European level and flatness standards and has trip hazards all over it; joint width is too large and not consistent and the joints are not correctly aligned; grouting has apparently been power-hosed out of the joints in an attempt to remove grout from the surface of the flags, which seem to be stained by the grout.

A spokesperson for Gwynedd Council, which is responsible for Caernarfon, said the council was “very happy” with the paving.