"At first people were just walking through it, it looked like dust particles and then all of a sudden people started panicking, hitting themselves, trying to get them off."
Crowds gathered in London to take pictures of the unusual sight. Luckily, Tony Mann, a project manager at nearby John Lewis and a trained bee keeper was on hand to provide assistance and help smoke the European honeybee colony out.
Mr Mann, who donned a white bee keeping costume and netted hat for the tricky task, said: "We have either had a virgin Queen or an old Queen, she has left the nest and she has brought the warm and settled on the shop front."
He said some of the bees were flying around the area "like scouts to try to find out where the next best place to go is".
The colony was later safely moved across the road to Westminster Cathedral, where it will be looked after by beekeepers on top of the Catholic church's roof.
It is not known where the bees originally came from, but a string of shops in the local area do have their own hives.
Passers by check out a swarm of about 5,000 honeybees that have been attracted to a discount sign on the window of a shop in central London. Photo / AP / PA / Philip Toscano
David Beamont, operations manager at the Victoria Business Improvement District (BID), which manages the interests of businesses in the area, said trained keepers arrived quickly on the scene to deal with the situation.
He said: "In Victoria there are over a dozen experienced beekeepers who have all been on an intense training course that focuses on the theory and practical training of urban beekeeping, successfully managing hives for nearly two years.
"Local beekeepers were able to respond swiftly to manage the swarm, collect them in a mobile hive and move them to a suitable location. Our ambassadors were also on site to reassure members of the public that the bees were not distressed."
Ruth Duston, CEO of Victoria BID, said local businesses kept bees to boost the area's biodiversity.
She said: "With a falling national bee population, the bees in Victoria play a key role in showing that London is a healthy, liveable city."
- The Independent with additional reporting by Press Association