The connective cells, known as fibroblasts, are then isolated and an electrical current is used to force-feed them with the snippets of DNA that make factor VIII.

BBC: Genetics work eases haemophilia

The force has said it was believed to be an isolated incident and that there was no risk to the public, but patrols have been stepped up in the area.

BBC: Sasha Marsden stabbed to death in Blackpool alley