On 16 October, council workers and postal workers in London made a demonstration of workers' solidarity in action not seen for many years.
Two different unions, organising in different industries, struck together, on the same day, for the same demand: an increase to £4000 in London pay weighting.
This simple, uniform demand has the potential to unify a vast range of workers, in a way that pay disputes do not usually do.
The Tory anti-union laws, kept in force by New Labour, make solidarity action unlawful, and thus vastly weaken the union movement. But even those laws could not ban different groups of workers, all with the same or similar pay demands, deciding to maximise their impact by striking on the same date.
Teachers, college lecturers, and college support staff, also have disputes in progress on the same issue. Every group of workers in London knows the huge costs of living in the capital.
A joint one-day strike, and a joint mass demonstration, by as many unions and groups of workers as possible, for increased London weighting with a minimum of £4000, would be something different from the routine one-day strikes which many trade unionists are now tired of.
It could lead straight into longer strikes by those groups of workers confident enough to undertake them. It would boost workers' confidence right across the country, not just in London.
It could put on the agenda not just the pay claim, but a joint political campaign by the trade unions for government measures to bring affordable housing, adequate and affordable public transport, and affordable childcare to London.
Unity is strength! For a one-day London-wide public-sector strike and demonstration!