There are many unusual wasps and bees in my garden. I swear I see something new every day! I needed to look up this one gnawing the wood off my shed, to find that it is apparently a Median wasp drone, the largest of the UK paper wasps apart from the Hornet. I could hear it scraping the wood and it was definitely a shade bigger than the average wasp. It's quite a sleek thing, being largely black with just the slivers of yellow – a designer wasp perhaps.

Intriguingly that linked page suggests that these wasps can be dissuaded from attacking your picnic with a wave of the arm, whereas that only agitates the more normal UK wasps.