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From 16 October 1957 it ran between Purley High Street and Victoria Embankment. On 23 January 1966, the Sunday service was withdrawn with the exception of a few early morning journeys operated by Thornton Heath garage. On 31 October 1970, these journeys were converted to one-man operation (OMO) using single-deck AEC Swifts, with subsequent conversion to double-deck Daimler Fleetline operation from 23 March 1974.
On 3 February 2001, it was converted to low floor operation with Alexander ALX400 bodied DAF DB250s. Upon being re-tendered, Arriva London successfully retained with new contracts commencing on 1 February 2003 and 30 January 2010. On 31 March 2012, route 109 was transferred from Thornton Heath to Brixton garage.