All these arguments have been rolled out since the first UK cencus in 1801. It has happened every 10 years except 1941 (WW2). The data is actually secure, and not available to the government or it's agencies. The processed statistics are available to everyone. These are 2 distinct levels of information. If you really do want to measure immigration, the north/south divide or the pressure on resources, look at these figures, not the Daily Mail's!