Is this the lowest-headroom cycle bridge in Britain*? It’s on National Cycle Route 1 following the Lee Valley north, in Walthamstow marshes.
The cycle path ducks under a railway bridge at Coppermill Lane and leaves you just five feet of headroom, or 152cm – that’s about the minimum required width for a cycle lane.
(The minimum required headroom for underpasses according to TA90/05 appears to be 2.4m, or an inch or two under eight feet.)
This young lady has obviously had practice.
*EDIT: There’s an even lower underpass in Bedford, which I visited in Jan 2025.