A large collection of honey bees hanging from a branch will be making a pretty intimidating buzzing sound. They will be collected in a tight group which could number around 20,000 bees. Honey bees swarm to create a new colony somewhere with new foraging potential. It is their method of reproducing. When they first leave the hive, they will gorge themselves on the honey stores in the hive to enable them to produce lots of wax when they find a new location. When a bee is full of honey it is quite lethargic, much like us with a full tummy! So when the swarm first appears, it will be quite well tempered. This will change the longer they remain clustered waiting to find their new home.
If you have found a swarm of bees in your garden, then you can contact me on the email at the bottom. Honey bees are similar in size to wasps but are normally a dark brown when looked at from a distance. They will usually land on branches or such structures that allow them to form groups which wait for the scout bees to find a new home. They will mostly find a new home within a few hours but this could be in a location that will cause a nuisance to people in the area.
I can collect swarms if they are accessible and will take them away to ensure they don't set up home in someone's chimney. I charge a flat fee of £ 30 (Extra if it is more than 15 miles from Norwich).