Should Jeremy Corbyn’s dreams of mass nationalisations come to pass, with all its unaffordable consequences, then one day historians will try to work out who helped it happen.

Those dogmatists on the left who spent decades refusing to accept that any good could ever come of involving the private sector in anything will probably get a bit of the credit/blame, at minimum for keeping their flame alive even in the face of the evidence. But, sad to say, far more of the responsibility will be allotted to the private rail operators.

Seriously: who has been a better recruiting sergeant for the cause of nationalisation, rail firms or John McDonnell? There’s no contest – while the industry overall has achieved quite remarkable things in terms of passenger numbers, the behaviour and failings of various operators has driven many people into the arms of left-wing economic ideology. From micro failings like poor customer service to macro failings like today’s news that Virgin Trains East Coast has breached its contract, each error is not just an annoyance to passengers but a gift to those who want to bring rail – and a host of other industries – back into the state’s ownership and control.

Perhaps Sir Richard Branson and Sir Brian Souter aren’t bothered about such an effect, or feel safe from the job losses, soaring taxes and economic stagnation of a Corbynite Britain. But you might have thought that self-interest at least would caution them to do a better job. After all, both men’s companies – Virgin and Stagecoach – also continue to seek to operate elsewhere in the rail system, even as their joint East Coast venture gets into trouble. Extraordinarily, Stagecoach is reportedly shortlisted for a new franchise in the East Midlands – because, as the Guardian reports Chris Grayling saying, ““The government has no legal grounds to restrict Stagecoach from bidding.”

Perhaps they cannot be forbidden from bidding, but it’s high time such companies were held to account for their failures when it comes to shortlisting or awarding franchises and other public sector contracts. If you breach one service contract, you should not be able to waltz in, whispering sweet nothings to a different arm of not just the same state but the same service, as if butter wouldn’t melt. You certainly shouldn’t be in the running for such a contract while one you already hold is collapsing around your ears. If the legal rights to do so aren’t established in existing contracts, write them into new contracts, and use them strictly in future.

For any market to work, there must be consequences for failure as well as rewards for success. Holding firms accountable when they get things wrong would be good practice, good for taxpayers, good for passengers, good for the Government and, in the longer run, good for the reputation of privatisation as a whole. Show these companies some tough justice, and we all gain.