This wasp is "sharing" my plate of free range roast pork on a summer's day in a pub garden - with my consent! Most people fear and hate wasps and tend to swat at them wildly, making them much more likely to sting in self defence. I find them fascinating and beautiful and most of my friends and colleagues think I'm strange.
But not all of them! Buglife is running a campaign to educate people about all the helpful things wasps do for us and trying to persuade people to stop swatting them. Have a look at buglife.org.uk .
Social wasps - the kind which try to share our picnics and cream teas in late summer - eat a lot of garden "pests", including aphids, flies and caterpillars. They build intricate nests of hexagonal cells by chewing up wood and turning it into paper and there the sterile female workers tend and feed the growing grubs.
By late summer the grubs have developed into adults and left the nest. The workers are no longer being fed sugary liquid secreted by the young and need to find other sweet feasts. This is when they are most likely to come into conflict with people.
In my experience, wasps rarely sting unless provoked. If you want to lure them away from your plate, try giving them a drop of sweet drink or jam on a far corner of the table. Then you might get the chance to watch and wonder from a more comfortable distance. (don't try this if someone in your group is genuinely allergic to wasp stings.)