[4][5] On 14 August 1916, a supplementary Monday - Saturday route 7A was introduced between Wormwood Scrubs and London Bridge station.

During the 1920s, route 7 was extended to Acton and a 7B was introduced as a Waterloo station to London Bridge, Monday to Friday peak hours only service via Holborn.

This gave the Metropolitan Police responsibility for bus operation and route numbering.

This situation remained until 3 October 1934, when the newly constituted London Passenger Transport Board instituted its own numbering system.

Route 7 continued with an extension to Kew Green until 22 August 1946, when the 7A was revived from Acton to London Bridge.

[9][10] In May 2021, routes 7 and N7 became the first in London to use double decker hydrogen fuel cell buses.

[12] A serious incident occurred on 13 June 1957, when a RTL-type bus on route 7A ran into a queue of waiting passengers on Oxford Street, killing eight people.