Hot on the heels of the recently-announced Crossrail for bikes comes this novel idea, proposed by design firm Gensler, to transform disused Tube lines into a network of underground paths for cyclists and pedestrians.

Though the concept has won favour in some places – it won Best Conceptual Project at the London Planning Awards at the beginning of February – it hasn’t been without its detractors. We can’t quite see how pleasant it would be riding underground when that’s what we’ve been trying to avoid the whole time…