"They have realised that public transport is not just for poor people," says Chris Antonopoulos, head of sales at Bombardier's rail division.

Among the most militant are Mark Serwotka—head of the Public and Commercial Services union, which looks after civil servants—and Bob Crow, who runs the Rail, Maritime and Transport union.

His giant mastiff came bounding out, looked between the marble pilings of the rail, and cocked his head to one side. He seemed to grin. He was looking right at us.