The unexpected death this week of Bob Crow, leader of the RMT Union (which represents many London Underground train drivers amongst others) has prompted quite a bit of media comment over the last few days. Tributes from industrial and political leaders have expressed sincere sadness, despite what his militant public persona might have led you to expect.

I never met Bob Crow, but it seems to me that he grasped more clearly than many that what most people want in their leaders is passion and an appeal to their emotions. At a time of generally falling Union membership, he doubled RMT membership, and then doubled it again, over a decade. I doubt that he could have done that by making a careful rational case. Stack that up against managers who – as public servants, charged with careful management of public money – are obliged to make their arguments rationally. Can you imagine what would have happened if politicians had incited Londoners to picket RMT headquarters when the tube went on strike? It is hardly surprising that he made an impact.

Recalling other powerful Union figures of the past – Arthur Scargill, say – isn’t that instinctive understanding of emotional leadership and the power of passion something they had in common? And perhaps the reason we now have a much less unionised and strike-prone world than we did is in part because union leaders have become less demonstrably passionate.

We need leaders who are passionate about their cause – whether in politics, in industry, or in unions – because passion is what galvanises the led. Whichever side of the argument you are on, we need more leaders who do that, as Bob Crow did.