Metal Industries, Limited was a conglomerate of mostly British engineering companies. It was founded in Glasgow in 1922 by Robert Watson McCrone. In 1953 its activities were described as "electrical and mechanical engineering manufacture and metal trading" In 1967, Aberdare Holdings of South Wales acquired a controlling interest in the group, but was quickly thwarted when M.I. created a large tranche of new shares which it sold to Thorn Electrical Industries, giving Thorn overall control of the company. The City Panel on Takeovers and Mergers referred to "abuses and inequities" that occurred during this chaotic takeover, among others at the time, but declined to recommend tougher regulations.
The subsidiary companies continued to trade as the 'Metal Industries' group of Thorn until 1970, when it merged with the George Cohen 600 group to become Six Hundred Metal Holdings. In 1976, Thorn sold its interest in the group to the government-owned British Steel Corporation.