Between blotch and blok

Posted by Unknown

http://diamondgeezer.blogspot.com/2025/12/live-facial-recognition.html

On Friday I went to Westfield in Stratford, arriving via the big footbridge that crosses over the station. It was busy with people walking to and fro.

On the far side, just before everything opens out to the shops, two cameras had been set up in the middle of the walkway.


(nobody was fiddling with the camera the first time I passed, I took this photo on my way back)

They were serious-looking cameras supported on a tripod, like something you might find pointed towards you in an operating theatre or dentist's chair. One pointed towards those arriving on the left-hand side and the other those arriving on the right, ensuring there was no way you could walk past without being scrutinised. Cables connected the cameras to a power/communication gizmo on the floor and a ring of red plastic barriers ensured nobody walked into them. I wonder what that's about, I thought.

Outside the entrance to Marks & Spencer a big red van had been parked in the middle of the piazza. It had another camera on the roof, and another camera on the roof, also a globe camera on the roof, also sensors on the roof, also four tiny black plastic aerials stuck just above the windscreen. Two more globe cameras hung from a pole positioned beside the van, also another two on the other side of the van, also a sensor on a taller pole pointing forwards towards the cameras I'd seen earlier. A lot of yellow cables threaded out of the van, protected by a strip of blue and white police tape lest any shoppers accidentally disturb them.



I had a pretty good idea what this was but I asked anyway, approaching one of the gentlemen setting up equipment around the van. "It's for a facial recognition deployment we're doing later," he said. Well of course it was.

I was unnerved that the Met Police can just turn up in a certain area and start filming everyone, literally everyone that walks past. Sure there are already CCTV cameras everywhere in London but they're not necessarily good quality, nor are they being constantly monitored, nor do they have the specific intention of catching ne'erdowells going about their daily business. I start to see now why some teenagers who may or may not be lowlife insist on going everywhere with a mask across half their face.

But mostly I was reassured they hadn't started filming yet. I had no particular reason to be concerned, criminally speaking, but I still don't like being the object of overt surveillance while I'm out and about. They hadn't started filming when I came back either, this because they were only just getting the red signs out of the van saying Police Live Facial Recognition In Operation. Admittedly me taking photos of a set-up intended to take photos of me is a bit hypocritical, but at least my subjects weren't facing towards from the camera.

Yesterday I found myself at the crossroads outside Tottenham Court Road station, bang in the middle of the West End, and there they were again.



This time it was a white van rather than red, this time with a single pole supporting at least four cameras, but the intended outcome was the same. I presume this deployment was live because six police officers were standing around on duty, in two groups of three, ready to leap into action on a positive identification. But I didn't see a sign anywhere, perhaps because the crowds milling around were blocking it or perhaps because it was pointing a different way. I was especially uncomfortable at the lack of notification, if indeed it was live, as if this were a trap they were hoping people wouldn't notice.

Had I thought to check the Met's facial recognition webpage before I set out yesterday, I might have been warned.

On Monday 01 December 2025 we are deploying Live Facial Recognition Technology to crime hotspots in Waltham Forest, Camden and Westminster borough. The people we are seeking to locate at crime hotspots are set out in our policy.

Reading more, I discovered how Live Facial Recognition Technology (LFR) is undertaken...

LFR cameras are focused on a specific area; when people pass through that area their images are streamed directly to the Live Facial Recognition system and compared to a watchlist.

So it's about looking for specific people in specific places.

I also found out what the process is...

1. Construction of watchlist (this uses "images of Sought Persons", then analyses their faces as a set of numerical values)
2. Facial image acquisition (via a live feed of persons who appear within the "Zone of Recognition")
3. Face detection (software detects individual human faces within the images captured)
4. Feature extraction (software produces a "Biometric Template" of features of each detected face)
5. Face comparison (Biometric Template is compared with Watchlist Biometric Templates)
6. Matching (alert generated if "similarity score" surpasses pre-set threshold value)
7. Consideration of matched images (trained officer compares Candidate Image against Watchlist Image and takes action if required)
8. LFR data destruction (in the absence of an alert, Biometric Template immediately and automatically deleted)

So it's not just taking photos of everyone and stashing them away.

The policy document also explained what the definition of "a crime hotspot" is...

A crime hotspot is a small geographical area of approximately 300-500m across where crime data and/or MPS intelligence reporting and/or operational experience as to future criminality indicates that that it is an area where:
(i) the crime rate; and/or
(ii) the rate at which crime in that area is rising,
is assessed to be in the upper quartile for that BCU/OCU area.

That's at least 25% of the capital, so technically the Met could set up their scanners all over London.

Best of all I discovered the Met have provided data on all their LFR deployments undertaken this year.

In their 9 page document we learn that there have been 201 LFR operations this year (up until 21st November), an average of 4 or 5 a week. We learn that the Met's watchlist contains about 16,000 suspects (or 0.2% of the population of London). We learn that the average LFR session lasts just under 6 hours (maximum 9h 44m during the Notting Hill Carnival). We learn that the average number of alerts during a session is just 10 (95% of the time it's less than 20). We learn that only 12 False Alerts have been confirmed (a false alert rate of 0.0003%). We learn that 3,513,399 faces have been scanned altogether. And we learn that 1013 arrests have been made in total (an average of 5 each time).

I've also analysed where each of the 201 deployments took place. The most surveilled location is North End (Croydon) with 11 deployments, followed by Powis Street (Woolwich) with 8, then Stratford Broadway with 7 and Oxford Circus with 7. At least 30 locations have only been visited once. The most visited borough is Westminster with 32 deployments followed by Newham with 23. The only other boroughs with more than 10 visits are Croydon and Brent. Interestingly every borough has had at least one visit, as if the Met are deliberately ticking them all off (except for Barnet, Harrow and Kensington & Chelsea, although there are still five weeks of the year to go).

Excluding the Notting Hill Carnival, the highest number of faces scanned in one session was 47,659 at Oxford Circus on Thursday 2nd October. That's an average of 146 faces every minute. The second busiest location is Westfield Stratford which has had 30,000-40,000 scans on each of the four occasions they've turned up. The fewest number of scans was 2490 in 5¾hrs on Mare Street (Hackney) on Tuesday 6th May. The greatest number of arrests was 16 on August 12th on Brixton Road. On only six occasions did the Met drive off without making an arrest.



I'm now more reassured than I was before I studied the policy and investigated the data. The cameras are only being used to track 16,000 people and if you're not on the watchlist your data isn't retained. But it does seem wasteful to have despatched so many resources on 201 occasions and only come away with 1000 arrests, not all of which will have been for something very serious. It also continues to feel uncomfortable walking past these camera set-ups, even if you know you've done nothing wrong.

Live Facial Recognition is certainly a cunning way of creaming criminals off the streets who wouldn't normally be caught. If the police are doing their job well it can only help make us a little safer. But if the algorithm's off then the wrong people will be stopped, certain subgroups more than others, simply because they went out shopping. What I still find discomforting is the normalisation of intrusive overt surveillance on our streets without due warning, so on balance I'd be happy to see LFR deployments cease. I am perhaps less worried about now and more concerned about a future society in which the police and/or government use this technology in pursuit of a warped agenda, rooting out unacceptable citizens with the flick of a camera.

Watch out for yourself on our streets because they might be watching you.

http://diamondgeezer.blogspot.com/2025/12/live-facial-recognition.html