When the 657 figured in the final London trolleybus conversion of all, on 8 May 1962, Isleworth Depot was closed and its staff were transferred to nearby Hounslow Bus Garage (coded "AV"). The replacement motor bus service was provided by an extension of route 117, which up to then had run between Egham and Hounslow. In 1978 the 117 between Hounslow and Shepherd's Bush was superseded by an eastward extension to route 237. Until this time the 237 had operated between Chertsey and Hounslow with single deck buses – a truly suburban route. As part of the privatisation of London bus services, Hounslow Garage passed to London United that later was purchased by Transdev and later over by the RATP Group.