I was called to the Barton Fields allotments to see a swarm of bees on a bush. By the time I arrived it had fallen onto the ground. I placed a box next to it and gently scooped some bees into it. Quite quickly there was fanning and the remainder marched in. The whole catch must have taken no more than half an hour.
I gently cycled home with the box on my bike. It turned out that the box was slightly damaged so a couple of dozen bees escaped. I left them in a cool place and marched them into a hive the next morning.