This is an all-black wasp of unknown species, whose point on this page is simply to highlight that wasps come in flavours other than stripy black and yellow. In fact there is a very wide variety of solitary wasps that live in holes in trees, in the soil etc. and lead fascinating lives. This American page shows off some of the variety (albeit including hornets and sawflies). Personally I'm grateful that UK varieties don't stretch as far as this monster though.
I’ve been stung by one of those! It got blown up my sleeve by a breeze and immediately stung me as soon as it was free and flew away. The sting made me instantly come up in hives for at least two inches around the site of the stinger being inserted. Luckily, I was less than a minute away from my home at the time and it only took one dose of anti-histamine tablets to calm it down.
I just noticed that I have one of those living in a small, pencil-size, hole in the brickwork at my back door. At first I thought it was a large flying ant queen, until it went into its hole. It’s about 1 to 1.5 cm long, and moves with rapid, jerky movements, coming and going every few minutes.
Found one of these that had killed a large garden spider was dragging it across the back window of my car have pictures of it compared it to the great black wasp looks very much the same