In 1958, Elsie Shutt founded one of the first software businesses in the US, CompInc, when Bill Gates and Steve Jobs were both only three years old. Mark Zuckerberg wouldn’t be born for another three decades. A year later, Dina St Johnston founded the first British software company. Stephanie Shirley, another pioneer, started her business in 1962.

Many of the pioneers of computer programming were women. Through the post-war decades women were making key contributions to the birth of a new industry and more and more were choosing to study the subject at university. Then, suddenly, they stopped. What happened?