As you may know, we're big fans of CCTV in the UK. At the last count there was around 6 million CCTV cameras in the UK, or about one for every ten people living here. Most of these cameras are passive: they don't actually do anything, except for constantly recording to a tape or hard drive.
The big exceptions are real-time police and intelligence cameras, such as the the UK's automatic number plate recognition (ANPR) system. Here, in addition to storing the data on hard drives, number plates are actively interrogated and matched against a database of missing vehicles and wanted people.
The UK's police and intelligence agencies probably have similar real-time matching abilities with other private and public CCTV networks, though that information is obviously hard to come by. Most recently, though, the Metropolitan Police asked for access to Transport for London's ANPR network so that it can carry out real-time facial recognition on all motorists entering London.