For many years the British pub­lic has often been told that the United King­dom has 4.2 mil­lion CCTV cameras—that’s one for every four­teen residents—as widely quoted by politi­cians, var­i­ous media, and even the police.

This sta­tis­tic is rarely ques­tioned, but thanks to a recent episode of the excel­lent More or Less (UK-only?) sug­gest­ing that this sta­tis­tic was, at best, dubi­ous, I decided to do some reading.

I didn’t have to read much.

The sta­tis­tic comes from a 2002 report from the URBANEYE project, look­ing at the preva­lence of video sur­veil­lance in Lon­don (pdf). From the Conclusion:

In our Put­ney sam­ple, 41% of premises had CCTV sys­tems in oper­a­tion. These insti­tu­tions had an aver­age of 4.1 sur­veil­lance cam­eras. If we use these fig­ures to extrap­o­late the extent of CCTV cov­er­age in Lon­don and the coun­try as a whole we come up with the fol­low­ing results. If we begin by assum­ing that the extent of CCTV cov­er­age in Put­ney is broadly rep­re­sen­ta­tive of CCTV cov­er­age across the whole of Lon­don, we could esti­mate that 41% (102,910) of the 251,000 busi­ness reg­is­tered for VAT in Lon­don would have a CCTV sys­tem. Between them these busi­nesses will have 421,931 sur­veil­lance cam­eras. If we add to these the num­ber of sur­veil­lance cam­eras oper­at­ing in other pub­lic insti­tu­tions (open-street sys­tems, trans­port, hos­pi­tal, schools etc.) it would not be unrea­son­able to ‘guessti­mate’ that Lon­don­ers are mon­i­tored by at least 500,000 CCTV cam­eras. This means that in Lon­don (with a pop­u­la­tion of 7.2 mil­lion res­i­dents) there is approx­i­mately one cam­era for every four­teen peo­ple. From these fig­ures we would sug­gest that in the UK (with a pop­u­la­tion of almost 60 mil­lion) there are at least 4,285,000 cam­eras in the UK.

The Put­ney sam­ple was a pal­try 211 premises. And Put­ney, as one of the 35 major areas in Greater Lon­don, is hardly rep­re­sen­ta­tive of the UK as a whole. Even the CCTV User Group says the results are “extremely questionable”.