Aren't we already the most watched citizens in the world with the number of CCTV cameras? If UK liberty and UK security were a weighing scale then the balance already sits comfortably with security.
Capita, though not a government department, raised suspicion over people's benefits simply because they lived above a "WH Smith" which lead to them being stopped. It may be a lack of understanding that introduces suspicion and that can spiral into something much worse for an innocent person.
There is potential that the mountain of data leads to searching for a needle in a haystack and the action that needs to be analysed is lost.