The apparent success of the City and South London triggered an avalanche of bills for Tube railways, and in 1892 a Joint Select Committee of Parliament set out some ground rules.

“Now,” said Bobbit, with an amazing chuckle for a boy who was going to give to-morrow’s dinner to another boy, “you walk right along as ef you was going to walk a mile, and when you see I ’ve doven — dive!” The next they knew after that, Bobbit had “doven” into the old engine boiler, and they after him.

... and then this whirlybird that I headed for, I had my goggles off...

It may have been delivered direct to the saucery by the wardrobe clerk, but this can not be proved, as the 'Black Book' lacks an independent 'sausery' section.