London Buses route N21

History
London Buses route N21 was started in 28 June 1995 replacing routes N61 between Lewisham and Sidcup, and N62 between New Cross and Foots Cray, thus the service was extended via 21 to London Bridge before going their own way to Trafalgar Square and subsequently to Victoria.

The Bexleyheath allocation was added on 8 November 1997, and subsequently in 1999 the route was re-structured again with the extra weekend journeys via New Eltham being revised to operate from Eltham to Chislehurst via Mottingham and was introduced to run every night (not just weekends). The original service to Foots Cray via Blackfen and Sidcup remained unchanged. Changes to the frequency meant buses running every 30 minutes between Victoria and Eltham then every 60 mins to Chislehurst and Foots Cray respectively.

In 2002, another re-structure saw the Chislehurst Journeys withdrawn and run through to Foots Cray. Instead, providing a 30 min service over the whole route. The route was also shortened to start and terminate at Trafalgar Square as opposed to Victoria. On Friday and Saturday nights, patronage was such that extras were introduced between Eltham High Street and Trafalgar Square, combined with the Foots Cray Buses providing a 15-minute service over that section of route. With the withdrawal of the Chislehurst Services, Mottingham and Chislehurst were without a night bus route until Feb 2008 when the N136 was introduced (replacing parts of the N36).

The route was further amended on 10 October 2009, being withdrawn between Blackfen and Sidcup, instead running to Bexleyheath via Blendon, Bridgen and Old Bexley along the established day route 132. The Night service to Sidcup was simultaneously replaced by a 24-hour service on route 321, restoring a night service to New Eltham after an absence of 10 years.