Go to the nest in the later evening when they're all in, take a half pint of petrol and a polythene sack.
Tip the petrol into the entrance hole, leave the bottle in the hole it helps to block it up. Cover it with the sack and weight the sack down so it can't blow away.
Next day there will be a few wasps who were out on a sleepover somewhere and that will be all. The petrol fumes kill the nest off.
Don't light it a) it's dangerous and b) you're burning the vapour off and it's the vapour that does the job!
Guaranteed to work, trust me I'm a beekeeper.