Biggest strikes in UK/British history

In terms of days lost there would have been many strikes, which dwarfed yesterday's. For example a relatively small strike which I was involved in in the 80s would have resulted in about four times more work days lost than yesterday's (180,000 workers times three and a half weeks). Taken on this basis the 1984-5 miner's strike would clearly have been the biggest by far.

Devrim

If 2 million workers were out, N30 would have meant 2 million lost strike days. Add to J30 and that's maybe 2.5-2.75m this year in the two major strikes, topped up by all the smaller/local disputes around the place maybe nearer 3 million. 1926 was about 160 million strike days lost, while '79 and 84-5 were in the region of 30 million. So in terms of annual strike days, it's nowhere close. In terms of one day action, in terms of absolute strikers probably the most ever ('26 peaked at 1.5-1.75 million), but not in percentage terms as the labour force was smaller in the past. That's probably because in the past, there were lots more disputes going on, and for a longer period of time, whereas this year has so far seen mainly big one-day set pieces.

Green is strike days, read off the left axis. Source: ONS.

What about lost money. Is there a good consensus on what the largest single cost to huge multinational corporations/the UK economy has been from a strike in UK history?

I would imagine that it would be a mass solidarity strike somewhere from the great labour unrest period.

I imagine the big transport strikes during that period, especially the Liverpool dockers' and general transport strike, cut into production very significantly in large parts of the country.

Good point.

Political content is also important in assessing strikes. The years 1910-1914 saw tens of thousands of workers on strike for long periods with some of them taking on an insurrectionary scope. Unlike the peaceful strikes of the late 1800s, these were anything but and unlike the union recognition strikes of the late 1800s, many of these were explicitly anti-trade union. From 1911-12, widespread unoffical action led to a 4 week national strike involving a million workers; there was self-organisation, unofficial strike committees, workers using force, widespread sabotage, violent fights with strikebreakers and the military as well as agitation among soliders.
In 1913, eleven million strike days were lost (see "Mass strikes in Britain: 'The Great Labour Unrest' 1910-14" on the ICC's website).
The movement came to an end with the Dublic Lock-out and the reinforcement of the Triple Alliance, ie, the unions took back control. The Triple Alliance of the unions was instrumental in the defeat of the working class in 1926.

Similar for the "Winter of Discontent": self-organisation, strikes against the unions, unofficial actions, as a whole, at its height involving 1.5 million workers (many staying out for some time). Like 1910, it was part of an international wave of struggle and a response to the developments of the economic crisis. When that particular strike wave ended around February 1979, 29.474 million strike days had been lost.

Although 1926 was a defeat, there were localised struggles which, had they crossed over, clearly had the potential to challenge the very foundations of the system itself. Worth paying heed to the ferocity of the working-class's fightback during that period, the accounts of control of huge swathes of cities and towns, it was quite extreme at times.

The great unrest had very extreme political content and apparently 70 million strike days were lost all-in-all from approximately 1910-1914. I think that the hit on production must have been biggest here too, there are some references but mostly in books which amusingly refer to it as the 'edwardian labour unrest', if there's any more anyone can add on lost output during that period would be appreciated.

Generally agree with Communal Pie above. Despite the subsequent (profound) defeat, class militancy was resurgent throughout the early 20s up to 1925 and millions of workers responded to the TUC's strike call ("beyond all expectations" it said). The first issue of the TUC's paper - "The British Worker" suggested that sport and entertainment should be promoted, including football matches between strikers and police. The unions did their best to strangle any form of self-organisation that had existed from 1910-14 and in the early 20s and this was compounded by the careful preparation and actions of the ruling class - who, at some levels, were well aware that the trade unions were on their side.
During the strike, attempts were made to form workers' militias which were condemned by the unions and their Trade Councils. At the end of the official strike, called off after secret negotiations, the numbers of workers on strike actually rose and unofficial action continued.