How we source and present statistics

Last updated May 2026

1. Sources

Each policy theme on Westminster Brief carries one headline statistic drawn from an authoritative government source. The table below shows the source for each theme.

Two themes (foreign affairs, parliamentary affairs) have no single plausible national headline statistic and are not currently covered. These will be reviewed for future releases.

2. How figures are extracted

Westminster Brief runs a weekly automated refresh job every Monday morning. For each statistical series, the job fetches the source directly — either from the ONS API (for Office for National Statistics timeseries data) or by loading the bulletin landing page published by the relevant government department.

For ONS timeseries data, the latest observation is read directly from the ONS Beta API using the series' unique identifier (CDID). No interpretation is involved — the figure is taken as published.

For departmental bulletins, an AI system (Google Gemini Flash-Lite) reads the page and extracts the headline figure, unit, and time period. The verbatim sentence containing the figure is also captured. Before any new bulletin source goes live, a human spot-check is required. The extracted figure is displayed alongside the verbatim source sentence so you can verify it in seconds.

3. How plain-English summaries are generated

Each stat card shows two pieces of text alongside the headline figure:

• Source wording — a verbatim sentence from the official publication that contains the figure.
• Plain English — an AI-generated one or two sentence rewrite of the source wording in plain language.

The plain-English summary is generated by Google Gemini Flash and is strictly bounded: the AI may simplify language but may not add information, comparisons, or implications not present in the source sentence. The rewrite is only regenerated when the underlying source wording changes — not on every weekly refresh.

The verbatim source wording is displayed alongside every plain-English summary so you can check the rewrite against the original in the same view. Both are sourced from the official bulletin linked on every card.

4. Refresh cadence

The refresh job runs automatically every Monday at 06:00 UTC. Each source is fetched in turn. If a fetch fails, the last known figure remains on the page with a "(figure may be outdated)" annotation if the data has not been updated for more than 14 days.

Different sources publish at different cadences: ONS timeseries series are typically monthly or quarterly; departmental bulletins vary from monthly to annual. Westminster Brief displays whatever figure was most recently published — it does not attempt to predict or estimate missing periods.

5. Reporting errors

Each stat card has a "Report an issue" link. Use it if you believe a figure is wrong, out of date, or the plain-English summary misrepresents the source. Reports go to Westminster Brief for review. Include the correct figure and a link to the source if possible.

For urgent corrections, email hello@westminsterbrief.co.uk.

6. What Westminster Brief is not

Westminster Brief is not:

• An official statistical source. All figures originate from the department or body listed as publisher.
• A substitute for the publishing department's bulletin. The bulletin is the authoritative version — Westminster Brief surfaces it, not replaces it.
• Authoritative for academic citation, parliamentary submissions, Freedom of Information responses, or media publication without direct verification against the source bulletin.
• Guaranteed to be current. While the weekly refresh job captures most updates within days of publication, some bulletins publish irregularly or on schedules that fall between refresh windows.

When accuracy matters, always verify directly against the source publication linked on every card.

7. AI disclosure

Westminster Brief uses AI in two places in the statistics pipeline:

1. Extraction (Google Gemini Flash-Lite) — reads departmental bulletin pages and locates the headline figure. Applied to non-ONS sources only. ONS figures are read directly from the API without AI involvement.
2. Plain-English rewrite (Google Gemini Flash) — rewrites the verbatim source sentence in simpler language. Bounded to what the source sentence contains. Does not add interpretation.

Both uses are disclosed on every stat card with the label "Plain English summary generated by AI." The verbatim source sentence is displayed alongside every AI-generated rewrite so the output can be checked against the original.

Verify against source before use in published material.

8. Upcoming releases

Each topic brief page shows upcoming official statistics from the GOV.UK release calendar, where they exist for that topic's policy area. These entries are drawn directly from government departments' published release schedules.

Dates may be provisional and can change without notice. Confirmed dates are shown without a label. Provisional dates are explicitly tagged "Provisional date" so the distinction is always visible. Cancelled releases are excluded automatically.

The release calendar is refreshed daily from GOV.UK. Source: GOV.UK statistics release calendar.

Questions about this methodology? Get in touch.

See also: How Parliament makes laws — a guide to the bill stages and legislative procedure behind these statistics.