“We [reformed pensions] without strikes and under Labour the number of days lost through industrial disputes fell to its lowest-ever level.” Ed Miliband, 28 June 2011

With teachers and border agency staff due to take to the picket line tomorrow, the politics of industrial action have been on the mind of many in Westminster.

At this afternoon's Prime Minister's Questions, David Cameron accused his opposite number Ed Miliband of ducking the issue by failing to mention the impending strikes, claiming that he was “in the pocket of the unions”.

However the Labour Leader did set out his position on the strikes in an article on his website (quoted in today's Mirror), urging both the unions and the government to go back to the negotiating table. This, he claimed, was the approach that the Labour government had successfully pursued, leading to the fewest ever working days being lost because of industrial action.

So is this actually the case? Full Fact took a look.

The Office for National Statistics records the number of working days lost each year due to strikes (defined here as the days worked per worker). Sure enough, these do show that a new low was reached in 2005, when 157,000 working days were lost as a consequence of industrial action.

However looking more closely at the figures, it is open to question as to how much this was due to Labour's negotiating tactics. As the graph below shows, the number of working days lost to strikes each year has been steady since the early 1990s, when the last Conservative government was in office.

Indeed this is no coincidence, as it was in 1992 that the Trade Union and Labour Relations (Consolidation) Act was passed. Among the measures this enshrined in law was the requirement for unions to ballot members ahead of industrial action and to inform employers of their intention to strike, making the process harder.

If we limit the analysis to the years after this piece of legislation, we can see that not only did Labour oversee the year with the fewest number of working days lost due to strike action, but also the year with the most (2002, when 1.32 million days were lost).

However comparing the mean number of days lost to strikes under the Major government of 1992-1997 and the Blair/Brown governments thereafter, Labour's record does seem to be slightly better, with an average of 591,000 working days being lost per year compared to 635,000 under the Conservatives.

Conclusion

Ed Miliband is right that Labour government presided over the low watermark for working days lost to industrial action back in 2002. However a longer-term view might suggest that owes as much to union reforms made under the previous Conservative administration as anything else, as the trend has remained broadly stable since the early 1990s.