Route 1 actually predates London Transport, first appearing in 1906 as a Vanguard (London Motor Omnibus Company) service between Cricklewood and Elephant & Castle via Edgware Road and the Law Courts. In 1950 route 1 ran from Lewisham (Rennell Street) to Willesden Garage via Lewisham Road, Deptford Broadway, Surrey Docks Station, Southwark Park Road, Bricklayers Arms, Elephant & Castle, Waterloo, Aldwych, Strand, Trafalgar Square, Charing Cross Road, Tottenham Court Road, Marylebone Road, Marylebone, Maida Vale, Kilburn High Road and Willesden Lane, except Saturday afternoons when services were curtailed at Marylebone. In 1956 the Marylebone to Willesden section was replaced by new route 176 Monday to Saturday, with a peak hour extention to Catford Garage. The 1 continued to run from Lewisham to Willesden Garage on Sundays. The following year the Monday to Friday section between Surrey Docks and Lewisham was replaced by new route 199. In November, all Saturday service was extended to Lewisham, and Saturday afternoon journeys were also extended from Marylebone to Willesden Garage. In 1959 Saturday peak journeys were added to Catford Garage. In 1962 the Saturday afternoon extension from Marylebone to Willesden Garage was withdrawn, and Saturday peak journeys to Catford Garage were also withdrawn. In November all peak journeys to Catford Garage were withdrawn. On Monday to Friday and Saturday mornings route 1 ended at Surrey Docks Station, with the Saturday afternoon extension to Lewisham. In 1965 Monday to Friday journeys were extended from Surrey Docks to Bromley Garage replacing part of withdrawn route 199, and Saturday service was re-introduced between Marylebone and Willesden. Sunday service was withdrawn in 1966 with the introduction of route 1A between Willesden and Greenwich. In 1969 the 1 was withdrawn on Saturday between Trafalgar Square and Willesden Garage. In 1971 it was re-routed via Baker Street, Oxford Street, and Charing Cross Road instead of Tottenham Court Road. In 1972 Saturday shopping hours journeys were extended from Trafalgar Square to Oxford Circus. In 1978 Monday to Friday journeys were withdrawn between Catford and Bromley, and Sunday service was re-introduced between Charing Cross and Surrey Docks, replacing route 1A. In September 1982 Sunday journeys were extended, now running from Trafalgar Square to Surrey Quays Station, but just seven months later Sunday service was again withdrawn, and once more replaced by a re-introduced 1A. In 1985 route 1 was withdrawn beyond Deptford, now terminating at Greenwich (Cutty Sark). Sunday service using one-man-operation Titans was also re-introduced at the same time, replacing route 1A for a second time. In 1986 Sunday service was extended from Trafalgar Square to Oxford Circus. From June 1987 the 1 was completely converted to opo and runs daily from Trafalgar Square to Bromley Garage via Aldwych, Waterloo, Elephant & Castle, Bermondsey, Surrey Quays, Deptford, Greenwich, Lewisham, Catford, Downham and Bromley. In 1991 Sunday service was once again withdrawn, and the route was shortened to operate between Aldwych and Surrey Quays Station only. In 1992 troute 1 was extended from Surrey Quays Station to Rotherithe Tunnel Roundabout via Salter Road and Brunel Road for with-the-flow journeys in the single direction only. The City terminus was changed to Holborn Station in 1992, and then to New Oxford Street (Centre Point) in 1994. Since then service has been transferred from London Central to Capital Citybus, then Blue Triangle and East Thames Buses.
Route 616 was an express route introduced on 15 June 1970, running Mondays to Fridays between Cricklewood and Oxford Circus via Kilburn, Edgware Road and Marble Arch, supplementing the 16. In latter days it was reduced to peak hours only, and was eventually replaced by route 16A (which has also now disappeared).
A more detailed (or at least more readable) history of route 1 can be found in Kenneth Warren’s book, The Motorbus in Central London (Ian Allan, 1986; ISBN 0 7110 1568 6).