United Kingdom
| Engine name | Engine maker | Place | Active
years |
Notes | |
|---|---|---|---|---|---|
| A | A.B.C. | All British Engine Company | 1909 - 1920 | ||
| A.B.C. Motors 1920 Ltd. | Brookland, Surrey | 1920 - 1923 | |||
| A.B.C. Motors Ltd. | Walton-on-Thames, Surrey | 1923 - 1971 | |||
| A.J.S. | A. J. Stevens and Co | ||||
| Abingdon | Abingdon Ecco, Ltd. | ||||
| Abtus | Abtus Ltd. | London | |||
| Advance | Advance Motor Manufacturing Lt d. | Northampton | 1903 - | ||
| A.G.E.
British Bull |
Agricultural & General Enginerring | ||||
| Ailsa Craig | Ailsa Craig | Chiswick, London | 1891 - | ||
| The Albert Gas Engine | William Buttersworth | Albert Works, Manchester | 1890 - 1894 | ||
| Alden | Alden Engine Company | Oxford | 1920 - | ||
| Allan Brothers | Ashgrove Engineering Works | Aberdeen | 1898 - 1955 | Taken over by Wilson & Co | |
| Allons | Alldays & Onions Co, Ltd | ||||
| Auto Diesel | Auto Diesel | Uxbridge, Middlesex | 1936 - 1970 | ||
| Ariel | Ariel Works | ||||
| B.S.A. | The Birmingham Small Arms Co, Ltd | ||||
| BAT | Bat Motor Co (J.A.P. Engines) | ||||
| W H Allen | W. H. Allen Sons & Company Limited
Queens Engineering Works |
Bedford | |||
| Norman | Norman Engineering Co | Upper Grove Street, Leamington Spa | 1919 - 1968 | The company was absorbed in to the Auto Diesels Braby Group | |