When, many, many years ago British Rail decided to close
Broad Street Station, as a sop to commuters coming via
Canonbury Tunnel, they built a chord in Hackney to enable
trains to run from the North London Line to Liverpool Street
during the morning rush hour. I assume these rush hour
services were abandoned decades ago.

I notice that the spur is still there and that the rails -
and absence of rust - suggest it is still occasionally
utilised. Does anyone know what it used for?