Ancient Robert the Bruce stained glass shows the treasure to be found in Scotland's charity shops

There are people who complain if a string of charity shops suddenly opens up on their local high street. For others, however, it is a marvellous opportunity – to go hunting for treasure.

It was in a charity shop that antique dealer Richard Drummond spotted a colourful piece of stained glass, caked in years of grease. After buying it for £20, he started cleaning it with bicarbonate soda and vinegar.

But, as the artwork gradually emerged from the grime, he began to sense that this could be something very old and switched to water. An image of what might be a knight appeared and then a Latin inscription: “Robert Rex Scotorum” or Robert, King of Scots.

Antique dealers Richard Drummond and his son Alfie with a stained glass window featuring an inscription that could be up to 700 years old and relate to Robert the Bruce (Picture: Katielee Arrowsmith) | SWNS

Experts on the BBC's The Bidding Room programme have now said the stained glass could be up to 700 years old, so it’s possible it was made during Robert the Bruce’s lifetime. Drummond said: "It could be priceless. If this is proven to be of that period, it's a massive historical find for Scotland.” Further tests are planned.

So next time you’re walking past a charity shop, maybe pop in for a bit... fingers crossed!