Do we really have ‘superflu’?

December 17, 2025·29 min·2 clips

Prison staff calculate release dates by hand from 150-page guidance documents — and that is why people are being let out at the wrong time.

The headline claim is winter superflu. Tim Harford slows the phrase down right away, asking whether the outbreak is actually unprecedented or simply flu with better branding. From there, the running order opens out: flu numbers, prison releases, emigration under Labour, and the US economy. The strongest excerpt is on migration. A claim about Britons leaving the UK gets tested against the awkward reality of counting people who do not have to log their departures. Holidays blur things further. Madeleine Sumption explains that British citizens can move in and out freely, so counting emigration is harder than counting people with fixed visa periods. The data is still experimental. The Office for National Statistics is trying newer methods, and Sumption expects revisions rather than a tidy answer. That matters. The figures suggest more British citizens are leaving than arriving, by more than 100,000 a year, but the programme keeps asking what is inside that number. Dubai and Milan lose some shine. UN data points instead toward Bangladesh, Poland, and Romania, countries tied to earlier inward migration to the UK. The story gets less flashy and more complicated. Some leavers may be former migrants who became British citizens. Others may be UK-born citizens moving because of family ties abroad. English-speaking destinations are still in the mix, with Australia, the US, and Canada named as likely major destinations for British-born British citizens. The trend question remains open. With the current method only going back to 2021, the programme will not pretend a short run of data proves a long-term pattern.

As heard by us

A calm check on winter pressure, emigration claims, and what the numbers can actually support.

More or Less opens a new series by treating big claims as something to test, not admire. Tim Harford moves from winter pressure on the NHS to prison release habits, then to talk of mass emigration under Labour and the claim that the US economy cannot grow at 25% a year.

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Press play if you want the headline checked before the panic spreads.

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