Jesse Jackson calls it the “we can’t find them” syndrome. The civil rights activist wants Silicon Valley to hire more black people and has little time for the most common excuse: that suitably-qualified African Americans are hard to come by. “They have the best, most resourceful researchers in the whole world. They know where everything is and yet they look in parts of Asia rather than parts of Oakland.”

Rev Jackson has recently taken his decades-long fight for racial equality to the tech industry. In recent months he has toured the annual shareholder meetings of Google and Facebook, arguing that their workforces – dominated by white and, to a lesser extent, Asian males – need to reflect their customers better.

His pressure has led to the publication of diversity reports by companies that show the extent of the issue: African Americans make up 13 per cent of the US population but less than 5 per cent of the domestic workforce at most major tech groups, and are particularly rare in tech-focused roles in these businesses (see charts); women form only about 30 per cent of their global workforce.