Changes over the past decade to the ways in which data on strikes is collected and published risk undermining the value for academics and policy-makers of a series which has been running since the 1890s, according to an analysis by industrial relations specialist Dr Dave Lyddon.

In an open access article for the Industrial Relations Journal, Dr Lyddon argues that the most recent change, which means that a multi-union or multi-employer dispute is no longer categorized as a single strike, means that the ‘strike surge’ recorded in 2022-23 has been exaggerated in the data.

He warns that changes to the ways in which the data is collected and presented mean that those making public policy on industrial relations can no longer see trends over time or make informed decisions based on comprehensive information.

The changes also have an impact on academic users of the data, who have until recent years been able to rely on a statistical series that dates back to the time when John Burnett became the first ever labour correspondent at the Board of Trade.

Writing in the Journal, Dr Lyddon argues that the first significant change to the series came in 2015, when ‘out of the blue’, the Office for National Statistics ended a longstanding rule that a new stoppage would be recorded if there was a gap of at least a month between incidents of discontinuous strike action in the same dispute.

As a result of this change, the numbers of one-day stoppages and of all stoppages recorded in the data fell markedly, as what would have been previously noted as several disputes were now recorded as a single event, while the median length of disputes appeared to increase.

The second significant change followed in 2022 when the ONS began to count strikes involving more than one employer (as, for example, in public sector disputes involving several NHS trusts) or more than one trade union as separate stoppages.

The effect of this was to dramatically increase the number of stoppages in the official data. In fact, although the number of days lost to strikes was high during 2022-23 when there were several large-scale national pay disputes, including at Royal Mail and among schoolteachers, he writes, the number of stoppages was of about the same order as in the pre-pandemic years.

Both changes mark a departure from the standards set by the International Labor Organization.

‘The simplest solution would be to reverse the 2022 revision of the definition of a stoppage,’ Dr Lyddon concludes. But even if that cannot be done, he says, there are other lesser changes which could be implemented without significant cost.

‘If such change does not happen, a periodically rich source of strike data, whatever their limitations, will have shrunk to little more than the one-dimensional “working days lost” indicator.’

Lyddon, D. (2025), The Sea Change in UK Strike Statistics, Implications for Public Policy, and Misrepresentation of the 2022–2023 Strike Surge. Industrial Relations Journal. Open Access at https://doi.org/10.1111/irj.12474

Also on this website…

The long view: three hundred years of British strikes: contours, legal frameworks, and tactics, by Dave Lyddon.

John Burnett and the origins of official labour statistics, by Mark Crail