Following several trials with small diesel shunting locomotives BR selected some of the best components for their own design, given TOPS class 03. These locomotives had a 204bhp Gardner engine and mechanical transmission, very similar to the Drewry 04 locomotives. The 03 was the designated standard small diesel shunter, examples being kept in service where required well into the 1980s. Withdrawn locomotives have found further use with industrial users and heritage railways.