John Broadwood is one of the oldest piano manufacturers in the world. In fact the company, founded in 1728, began making harpsichords before the inception of the piano. I think one of the largest contributing reasons that John Broadwood & Sons have been at the forefront of British piano manufacturing for so long is because of their illustrious nature and forward thinking.
One thing John Broadwood did think prudently about is the possibility of a woodworm infestation within pianos.
Woodworm are actually the larvae of woodboring beetles and there are several species of woodworm beetles in the UK.
With time, these woodboring insects will greatly reduce the strength of the timbers which they infect. As most of their damage is on the inside of the wood infestations often go unseen for several years before adult beetles emerge through 'exit' holes in the woods surface.
Fortunately woodworm treatment these days is very fast and effective so it is no longer a common concern, but back then it would have been devastating and would have almost certainly meant the end of the piano.
To circumvent any infestations John Broadwood & Sons applied this anti-woodworm paint (photographed in orange) which contains a complex mixture of chemicals to repel the prolific pests. The paint was applied to the parts of their pianos which are otherwise 'unfinished' and vulnerable to attack, such as back-posts, end grains on the soundboard and the bottom of the piano.
Interestingly (and slightly off topic), research from a new study suggests that the secret which makes 16th century Stradivarius violins resonate so sweetly may in fact be an anti-woodworm treatment applied at the of construction. The mineral-infused wood is one of the key differences between a 'Strad' violin and all violins and other stringed instruments made since.