Stuart Street extension overbridge at Highgate created after removal of old cable car lines.
The official opening of the bridge was in 1954 and completed the Stuart Street extension.
I believe the bridge was constructed initially without the road cutting being in place - in other words, the basic concrete bridge was constructed first (built on the ground), then the earth was excavated from beneath it on completion.
Photo (K111) by Alan Gilchrist
See also: Other construction photographs.