A local farmer to here was stung after disturbing a wasp nest and very sadly he died. whilst out picking plums etc there are a lot buzzing around the trees etc. Note to self be more careful and dont wear shorts.
I was brought up on a farm in Lancashire, we had an orchard (OK, it was a field with a few pear, damson and victoria plum trees). Wasps were such a menace that we had to hang jam jars with an inch of jam/water syrup and a few holes poked into the top to trap the wasps and I swear you could have 1/2 a jam jar full of wasp bodies in 24 hours.
Wasps are nasty in numbers, they scent the victim when they sting to focus the attack and thus disturbing the nest can be really bad. Seems pretty obvious but get em off you and get away as soon as you can. Don't think because there's only a couple on you it can't turn really nasty if there's a lot of them about.
Interestingly today we were out with the kids at a swing park with loads of wasps buzzing around the rubbish bins where folks had put their ice cream wrappers. I was walking ahead with my 5 year old and turned round to find my wife, who had been sorting out our 3 year olds shoes, sidling towards me saying a wasp was on her and nibbling at her.
I flicked the wasp away from a mole that she had near her arm pit and found that the thing had drawn blood. She wasn't stung, she was being bitten.
I have heard of this with North American Yellow Jackets but not the UK Common Wasp before.