A massive police operation was deployed in Manchester city centre today, with armed officers surrounding a former factory that, it is understood, now serves as a business premises with offices inside. Activity appeared to be focused around a range of caravans, and witnesses claimed to have seen a helicopter circling over the area. Store Street, near Manchester Picadilly Station, was taped off since about 10am.... Ducie Street was closed, too. The nature of the incident is unknown.As of 2. 45pm,