The first frozen food available in Britain in 1937 was fish. It was marketed under the brand name "Igloo" by the Birds Eye company, which had been founded by Clarence Birdseye. The fish was caught in the North Atlantic and quickly frozen on board the ship using a new quick-freezing technology that Birdseye had developed. The Igloo brand was a success, and the company quickly expanded its range to include other frozen foods, such as peas and spinach.

Clarence Birdseye's innovative quick-freezing technology revolutionized the way food could be preserved and distributed. It involved rapidly freezing the fish on board the ship immediately after it was caught in the North Atlantic. This quick-freezing process helped to lock in the freshness and quality of the fish, making it taste much closer to the fresh catch than traditional freezing methods. The result was a convenient and high-quality frozen fish product that could be enjoyed even when the fish wasn't in season.

The "Igloo" brand quickly gained popularity in the United Kingdom, and consumers were impressed by the taste and convenience of the frozen fish. The success of "Igloo" paved the way for Birds Eye to expand its product range to include other frozen foods, such as peas and spinach, which further contributed to the growth of the frozen food industry in Britain.

The availability of frozen food, starting with "Igloo" fish, marked a turning point in the way people shopped for and consumed food. It allowed consumers to enjoy a variety of foods throughout the year, regardless of the season, and it played a significant role in shaping the modern convenience food industry. Clarence Birdseye's pioneering work in quick-freezing technology and the introduction of "Igloo" in 1937 set the stage for the continued development and popularity of frozen food in Britain and beyond.