After reading the post about the bee problem, thought I'd ask about my wasp problem. I've got a Calor propane tank in the garden (1500ltrs) and since I moved in theres been a problems with wasps on the tank. Started off with a few wasps and now its built up over past few weeks to about 50 odd wasps on the tank and buzzing round it. Cant see a nest anywhere but it seems their numbers are growing everyday. Tried using some spray on bug killer on the tank but didn't do much, and everything else I've tried hasn't worked.

Anyone got any suggestions?