Looks like an L3 Class trolleybus, on the run to North Woolwich from Stratford Broadway. Withdrawn from this service when 80 vehicles based at West Ham were transferred away to the Finchley and Highgate depots on 2nd and 3rd February, 1960. They were replaced by Routemasters.
Thanks Roy - I remember it happening but had forgotten the date. The river front at North Woolwich was a very generous area accommodating both loading and discharge of vehicles from the ferry and the turning circle necessary for the trolley buses.