The company's founder Eric Kirkham Cole was born on 4 July 1901 at Prittlewell, Southend-on-Sea, Essex, and was educated at Southend Day Technical School, followed by a three-year apprenticeship. Cole and his future wife Muriel Bradshaw started out making radio sets in 1924.
William Streatfield Verrells, a schoolmaster and freelance journalist from Southend-on-Sea, wrote an article in a local newspaper asking if it was possible to power a radio set from the mains electricity supply rather than batteries. Cole saw a possible business opportunity and set about building his battery eliminator, which he later demonstrated to Verrells. Suitably impressed, Verrells joined Cole in a business venture, with Cole manufacturing the battery eliminators, and Verrells marketing them. In 1926 a private company E.K. Cole Ltd was formed with Verrells as chairman and Cole as vice-chairman. With the extra funding that was raised, the company set up a new factory at Leigh-on-Sea in 1927. After further expansion E.K. Cole Ltd became a public limited company in 1930, and moved to a spacious new factory at Southend-on-Sea. The company also began to concentrate on the manufacture of mains powered radios rather than battery eliminators which were becoming obsolete.
The company suffered a major financial setback in 1932, when a fire swept through its research and development laboratories. The blaze destroyed much of the design work for the company’s new range of receivers.
Ekco launched its first car radio at the 1934 Radiolympia exhibition. Another important development for the company was the introduction of bakelite cabinets for its radios. Initially these cabinets were made for the company in Germany by AEG, however the introduction of high import duties on the cabinets in 1931 led Ekco to establish its own bakelite moulding shop adjacent to its Southend-on-Sea works. The company employed famous architects such as Serge Chermayeff and Wells Coates to design its bakelite radio cabinets.
In 1935 Ekco made a substantial investment in Scophony Limited, the developers of the ingenious Scophony projection television system. Although the system showed great promise, its development was halted by the Second World War, and not resumed postwar.
Before the start of the Second World War, the Government decided to disperse certain production to locations away from obvious bombing targets. This led to a shadow factory at Cowbridge House, Malmesbury, Wiltshire, being established by Ekco. This was followed by other shadow factories at Aylesbury, Woking, Preston, and Rutherglen. The wartime headquarters of Ekco was based at Aston Clinton House in Buckinghamshire. Following the outbreak of war, the Southend-on-Sea factory was evacuated apart from the bakelite moulding shop whose large moulding presses could not be moved easily. Less than a year later, the empty factory was re-equipped to make wiring looms for aircraft such as the Avro Lancaster.
Malmesbury specialised in the top-secret development and production of the new radar systems as part of the "Western Development Unit". Radar equipment produced at Malmesbury during the war included the AI Mk. IV and AI Mk. VIII air interception radars, and the ASV Mk. II air to surface vessel radar.