If you have a swarm arrive in your garden please dont panic, they have not arrived looking to harm you. They are just en route to find a new place to live.
Honey Bees are vitally important to the food chain, helping to ensure we have food to eat.
Keep your children and pets at a distance and do not disturb the bees.
Visit the link below on the British Beekeepers website which will tell you what steps to take. if they are Honey Bees then someone will be able to come to your home and remove them for free.
If the swarm is a different type of bee or perhaps wasps etc then the site gives guidance on how to identify them and who to contact. https://www.bbka.org.uk/swarm