London Sovereign can trace its roots back to independent BorehamwoodTravel Services which ran a fleet that included ex-Kelvin Central MCW Metrobuses and Northern Counties Palatines bodied Leyland Olympians and a collection of other vehicles. In 1993 it won its biggest London Buses contract, to operate route 13 with leased AEC Routemasters in its orange livery. In August 1994, Borehamwood Travel Services was sold to the Blazefield Group's Sovereign subsidiary, with the two operations merged as Sovereign London. On 3 November 2002, the business was sold to Transdev, and renamed Transdev London Sovereign. After London United was transferred to RATP as a result of the wider Transdev group's merger with Veolia Transport in March 2011, London Sovereign became Transdev's only London bus company. In March 2014, London Sovereign was sold to RATP and resumed trading as London Sovereign.
Edgware garage was first opened by the London General Omnibus Company in 1925 with space for 24 buses, but there was plenty of room adjacent to the Underground station which had recently been built. In 1939 a new building was built next to the original building which was to become the new bus station, while the remaining open parking area was used to store vehicles for the trolleybus replacement program. In 1984 a new 100 bus garage was built on the site of the long closed Edgware railway station at a cost of £4.5 million. In 1992 plans were made to close Edgware garage as Cricklewood garage was to become a fully functioning garage with new facilities. The outdoor parking area and the bus station then became a midibus base in 1993, with a new bus wash and light maintenance facilities provided in the yard. In 1999, London Sovereign, having won some tenders for bus services in North-West London, took a 10-year lease on half of Edgware garage and invested in a new maintenance facility which was to replace its former base at Borehamwood. In late 2000, Metroline moved back into the other half of the garage, making it one of the few garages to be shared by two operators. On 25 July 2015 London Sovereign commenced operating route 326.
Harrow garage opened in 1994. It is RATP Group's smallest London garage holding just 42 buses. The low roof beam across the middle of the depot building was raised to allow double deckers. The garage has a plot of land next to it, owned by London Sovereign, which is now used to park most of the single decker's due to the 183 allocation, which started on 24 July 2015. The 183 is split between Harrow and Edgware with the majority of buses at Harrow. Route 183 is now fully allocated to Harrow, with routes 398 & H17 transferred to Park Royal to make room.
