According to a report on Gizmodo, the employees were concerned both over the use of AI in drone warfare and the company's political decisions and the degree to which the trust of users would be eroded by this decision.

As iTWire  reported last month, rank-and-file workers, along with senior engineers, had submitted a letter to senior management to protest against the company's involvement in Project Maven.

The letter had more than 3100 signatures and was published by The New York Times.

Among the reasons cited was that executives at the company had become more opaque about controversial business decisions and less inclined to discuss them with rank-and-file employees.

GOOGLE MOTTOS: A HISTORY

1999: Don't Be Evil
2003: Try Your Hardest To Not Be Evil
2008: Make A Reasonable Effort To Avoid Being Evil
2013: What Is Evil, Really, When You Get Down To It, I Mean Really
2018: *just a series of high-pitched giggles*

— MGK Hockey 1234 (@mightygodking) 28 March 2018

Some employees felt that using AI for the purposes outlined in Project Maven was wrong, that humans should be doing what could be lethal work, and that Google should have no part of military work at all.

Apart from Maven, Google is also trying to win a US$10 billion cloud contract from the US Defence Department which is to be awarded before the end of the year. But many employees believe there would be strong objections to providing cloud services to support combat operations.

Gizmodo quoted one employee who quit as saying: "Over the last couple of months, I’ve been less and less impressed with the response and the way people’s concerns are being treated and listened to."

Another said: "It’s not like Google is this little machine-learning start-up that’s trying to find clients in different industries. It just seems like it makes sense for Google and Google’s reputation to stay out of that.”

Apart from the Google employees, a coalition of workers in the technology industry launched a petition in April asking Microsoft, Amazon, IBM and Google not to get involved in Defence Department projects.

Their petition said: "We believe that tech companies should not be in the business of war, and that we as tech workers must adopt binding ethical standards for the use of AI that will let us build the world we believe in. Google should break its contract with the Department of Defence.

"DoD contracts between Google, Microsoft, IBM and Amazon break user trust and signal a dangerous alliance. Tech companies that have vast quantities of sensitive data from users across the globe shouldn't build offensive technology for one country's military."