The Department for Environmental, Food and Rural Affairs said the bee is to be captured and destroyed out of fear it could be dangerous to native bees. The British Beekeepers Association said the bee could carry non-native viruses that British bees can't fight off, or it could out-compete native bees for food.
The Toy family said the bee disappeared from their yard before it could be destroyed.
"We are taking prompt action to collect any cocoons from the house which will be then assessed by experts," a spokesman for the Animal and Plant Health Agency, part of DEFRA, told the Evening Standard. "We continue to work with the National Bee Unit and their nationwide network of bee inspectors to monitor the situation."