We tend to forget that strike action has become a great deal more rare than it once was. Between 1941 and 1990, there were more than a million working days lost to industrial action every year (and often many more than that). Since 1990, the number of days lost has only exceeded a million four times.

That’s a measure of Thatcher’s achievements in fighting back against unions which routinely abused the right to strike and ending the closed shop. Union membership has fallen dramatically, but we must also give credit for the reduction in strikes to the new culture in many unions which seek to work productively with management to minimise closures and job losses, and to overcome problems rather than simply downing tools at the drop of a hat.

But it isn’t a uniform picture. While the private sector has seen huge strides, the public sector has seen less improvement – in the last ten years, public sector strikes have generated the majority of lost days in each year. This is a disproportionate share – in terms of GDP the public sector makes up a minority of the economy and in terms of headcount it only employs about a sixth of the UK workforce.

That disparity becomes starker when one considers that the bulk of lost private sector days last year came from strikes in the transport industry, the most public service-like part of the private sector.

This week sees the latest instalment in that saga, with yet more strikes closing down Southern trains and ensuing misery for hundreds of thousands of long-suffering passengers.

There is no innocent party here other than passengers themselves. The unions are deliberately causing mayhem in the hop of obstructing perfectly reasonable changes to the service, for which their members will be compensated. The train operator is simultaneously guilty of routine incompetence which can be relied upon to disrupt services even when their staff aren’t striking.

The Transport Secretary ought to deal with the operator. But even if a more competent administration was in place, passengers still deserve certainty that their jobs and lives won’t be continually affected by strikes.

New regulations which raise the threshold for legal strike action are set to come into force next year. They will require a turnout of at least 50 per cent, and for the strike to be supported by at least 40 per cent of the total union membership, for action to be legal. This will help to prevent whose strikes which are pushed through on low turnouts by cliques of militant union members, despite apathy among the bulk of the workforce. If at all possible, the introduction of these new rules ought to be accelerated.

But the regulations wouldn’t have prevented this week’s Southern strike by Aslef. Turnout was 77 per cent, and 67 per cent of the union’s members on the railway voted in favour. That clearly has a more legitimate mandate than something passed on 23 per cent turnout and only approved by a tiny minority of members. In most cases it would therefore be reasonable, if inconvenient, to allow it to go ahead.

But the railways aren’t most cases, they’re a vital part of the nation’s infrastructure. For some other crucial functions – like the police, armed forces and prison officers – strike action is completely forbidden. If the rail unions persist in such widespread disruption, it might be time to reconsider the case for transport joining that list.