From Graces Guide
British Rola Company, loudspeaker manufacturers and aircraft instrument makers, of Minerva Road, Park Royal, NW10; later of Ferry Works, Summer Road, Thames Ditton, Surrey.
- 1934  British Rola was an offshoot of the Rola Company of Cleveland, Ohio, USA. British Rola began at Minerva Road, Park Royal, London NW10.
- 1935 With the worldwide recession, the boom in demand for loudspeakers hit Rola and its competitors. Another that was badly affected was Celestion. The two company's products were influenced by changes in the wireless receiver market. As the receiver became more sophisticated and smaller, so the loudspeaker began to be housed within the receiver cabinet itself, thus dispensing with the separate speaker unit. To keep in line with this new development both Celestion and British Rola designed and produced a series of smaller speaker units, often to the receiver manufacturer’s specification.
- 1937 Electrical and radio manufacturers. "Rola" Aircraft Instruments, of Ferry Works, Summer Road, Thames Ditton, Surrey. Telephone: Emberbrook 3402. Cables: "Voicecoil, Thames Ditton"
- 1938 British Rola was registered as electrical and general engineers, toolmakers and stampers.
- 1939 See Aircraft Industry Suppliers
- WWII. During the war, both Celestion and British Rola were restricted to the manufacture of one type of loudspeaker, the utility "W" type, these being produced at Ferry Works, Summer Road, Thames Ditton and at their dispersal works at Pans Lane, Devizes, Wilts.
- WWII. When War broke out, Rola opened a dispersal factory at Bideford in Devon, in the former garage of Messrs Elliot and Sons. Production for the war effort grew apace with the manufacture of the RAF B3 Vacuum Pump, several thousands of which were produced. These were followed into production by the Rotol Airscrew Feathering Pump, four of which were fitted to all British multi-engined bombers. The final product was the Integral Hydraulic Pump BH Mark IV, and all these items contributed in no small measure to the Forces’ need for reliable battle equipment.
- The British Rola motif was a picture of a bird on a branch with the words ‘The speaker you know by ear’. The factory was virtually self-sufficient, producing cones, suspensions, voice coils and transformers ‘in-house’.
- 1942 The American parent company transferred to British Rola the right to manufacture and sell in the British Empire (excluding Canada and Australia) and the Continent of Europe, Rola products as used in the aircraft, engineering, electrical, motor and radio industries.
- 1946 With the coming of peace, the British Rola dispersal factory in Bideford closed in January, personnel being transferred to Thames Ditton for the assembly of loudspeakers. Because of the lack of post-war building material necessary for extensions the Thames Ditton factory progress was slow, and the Devizes factory stayed open to ease the problem.
- 1947 British Rola acquired Celestion in April, together with a subsidiary firm, Pressmach, which originated at Woolacombe, Devon, and another small pressing firm, Belark, also came under British Rola control. The Investors Chronicle for 1946 reported that British Rola would be responsible for the production of considerably more than half of the loudspeaker trade in the United Kingdom, and the two companies together covered practically the entire export loudspeaker business.
- 1947 Listed Exhibitor - British Industries Fair. Manufacturers of Speakers for all types of Radio. Six models, energised or permanent-magnet type. Sizes from 5in. to 10in. (127mm to 254mm) diameter. (Olympia, Ground Floor, Stand No. C.1531A) 
- 1948 During July, Celestion ceased production at Kingston-upon-Thames, and production machinery and personnel moved to Thames Ditton as a consolidation of the two companies. The company title became Rola Celestion Limited, and Celestion was adopted and registered as the trade mark for the company’s product.
- As the post war market evolved and product demand was established, it became evident that the new wonder - television - would account for a large number of loudspeakers, although the radio speaker market was still strong. As the television population grew, so did the need for speakers and the Thames Ditton production lines were fully engaged meeting the manufacturers’ deadlines.
- 1949 Rola Celestion went into receivership and was acquired by Truvox, a company based in Wembley and well known for its Public Address loudspeakers and systems. These covered the whole spectrum of this market and included such units as horns and loudspeakers for cinemas and many acoustic devices for the Forces which Truvox had developed and produced during World War Two.