Methodology

LFR Monitor is an independent register of live facial recognition (LFR) deployments by UK police forces, built because no single official source tracks this consistently across forces.

Since court rulings such as Bridges v South Wales Police, police forces publish records of their LFR deployments to show the technology is being used accountably. But publishing data isn't the same as making it usable. The records are spread across dozens of force websites, in PDFs, spreadsheets and web pages, each with its own layout and terminology, which makes them hard to find, compare or add up. LFR Monitor brings them together in one place, in one consistent format.

This page explains how those records are turned into one comparable dataset, and where that process involves a judgement call rather than a simple fact.

What data is shown

Each row represents one deployment: one force, one location, one date. Where a force's own log records more detail than others — camera counts, intervention outcomes, alert-confirmation splits and so on — that detail is kept rather than discarded to fit a lowest-common-denominator schema. This means some columns are empty for some forces; that's a reflection of what was actually published, not a data collection error. A blank cell means the force doesn't publish that figure; a 0 means it published a figure of zero.

How the data is collected

Sources are force-published registers, PDFs, or spreadsheets — see each force's page for direct links to the source documents.
Figures are extracted into per-force canonical datasets, then aggregated into a UK-wide dataset.
Deployment logs are periodically re-checked and manually re-verified. Every force's page shows when its data was last updated.

Harmonising different forces' terminology

The hardest part of this project isn't collecting the numbers — it's deciding when two forces' different terms mean the same thing. That decision is never made silently. Three real examples from the current dataset:

Case	Decision
Merseyside publishes an estimated faces-seen figure rather than a directly logged count	Merged into the same "faces scanned" figure as other forces, but flagged on Merseyside's page as an estimate rather than an exact count.
Some of South Wales Police's earlier deployments have no recorded faces-scanned figure at all	Treated as a genuine historical gap (SWP began recording this metric partway through its deployment history), not an error — those rows show as blank, and are excluded from totals rather than counted as zero.
The Metropolitan Police's per-deployment "faces scanned" figures were coming out as zero for almost every row — inconsistent with their published annual totals	Traced to a column-mapping bug in the ingest script, not a gap in the Met's own published data: the figure was landing in the wrong field for most 2023 onward deployments. Fixed and re-verified row-by-row against the original source PDFs — the Met's faces-scanned figure is now published with the same confidence as other forces.

What's combined, and what's kept separate

Only figures that mean the same thing across forces are added together into UK-wide totals. Where forces measure different things, or bundle figures together, they're kept separate.

Figure	How it's handled
Faces scanned	Combined. Most forces log this as "faces seen". Merseyside Police and British Transport Police publish an estimate instead, which is included but labelled as an estimate.
Arrests	Combined wherever a force publishes a clear arrest count, even under a different heading (Merseyside's "outcome: arrest", Thames Valley's "arrests").
Total alerts	Combined. Every force uses it to mean the same thing: all alerts the system generated, true and false.
Arrests and disposals reported together	Kept separate. Several forces, including South Wales Police and Bedfordshire Police, sometimes report arrests and other outcomes in a single combined entry. These are never split up or guessed at, so they appear in their own "Arrests / Disposals" column, and the UK arrests total is a minimum for those forces.
True and false alerts	Kept separate. Some forces split alerts into confirmed and unconfirmed, others record only positive and incorrect alerts, and Bedfordshire records a single false-alerts total. Adding these together would mix different measures.
Interventions	Kept separate. Forces use this heading for different things, so it isn't totalled.
Watchlist size	Not totalled. The Met uses one large standing watchlist, while other forces build smaller lists for each deployment.

Why this matters: a site that quietly merged "estimate" and "exact count" into one number, or published an unverified figure because it looked plausible, would be making the data look more solid than it is. The goal here is to make publicly available data genuinely accessible and usable.

Accuracy and limitations

Forces use different definitions and reporting formats. Fields are kept faithful to their source rather than forced into agreement.
There will always be a delay between a deployment happening, the deployment record being published and it appearing here. The "last updated" date on each force's page is the measure of how current that force's data is.

Spotted an error, have a source this site is missing, or work for a force and want to correct something? Use the Contact page.