Route H37 was introduced in 1991, as a replacement for the western end of the very long route 37, which was divided into three separate routes - 37, 337, and H37.
The very busy 37 had always been worked by double-deck buses, but a low bridge at the northern end of St. Johns Road Isleworth caused an awkward deviation via Loring and Linkfield Roads. The H37 has always been single-deck-operated, and can travel the whole length of St Johns Road.
Initially the route was operated by 28-seat DT class Dennis Darts, but these soon proved too small, and certain journeys were operated by larger LX class Leyland Lynx.
In time the remaining Darts and Lynxes were replaced by Leyland Nationals that had been converted to single-door layout and been refurbished under the Urbanbus name, a scaled-down version of the Greenway scheme.
When the route was offered for tender in 1998, it was awarded to London United (now Transdev), and the buses were replaced by brand new low-floor Dennis Darts, which remain on the route today (2009).
In 2007 the Hounslow terminal was moved from the Bus Station to the New Blenheim Centre.
The terminal in Richmond moved from the station to Manor Circus on 27 June 2009
Although most Optare Tempos have arrived, some Dennis Darts still maintain on the service running occasional night trips. By September, all Tempos will replace the Darts.
