It is Scotland’s forgotten waterway – once the country’s most profitable canal, which transported 1 million tonnes of coal and iron a year but now near invisible unless you know where to look.

This was where the kings and queens of Scotland ... more or less abandoned and it is now a shell of its former self. To reach its fenced-off remains you walk down a hill from the canal and through ...

Back in the 1840s, work started on a railway that would create a link between the north of Edinburgh and Canal Street ... the Scotland Street Tunnel has mostly been abandoned.