The letter has more than 3100 signatures, according to  The New York Times, which published the missive on Wednesday.

Google announced recently that it would be providing help to Project Maven, a joint effort with the Pentagon, which uses video imagery in counter-insurgency and counter-terrorism missions. The project aims to develop artificial intelligence to analyse drone footage and identify objects within it

The letter, addressed to Google chief Sundar Pichai, said: "We believe that Google should not be in the business of war. Therefore we ask that Project Maven be cancelled, and that Google draft, publicise and enforce a clear policy stating that neither Google nor its contractors will ever build warfare technology."

Google's former chairman Eric Schmidt last year expressed concerns over such projects, saying: "There's a general concern in the tech community of somehow the military-industrial complex using their stuff to kill people incorrectly."

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

The letter went on: "Recently, Googlers voiced concerns about Maven internally. Diane Greene responded, assuring them that the technology will not 'operate or fly drones' and 'will not be used to launch weapons'. While this eliminates a narrow set of direct applications, the technology is being built for the military, and once it’s delivered it could easily be used to assist in these tasks.

"This plan will irreparably damage Google’s brand and its ability to compete for talent. Amid growing fears of biased and weaponised AI, Google is already struggling to keep the public’s trust. By entering into this contract, Google will join the ranks of companies like Palantir, Raytheon, and General Dynamics.

"The argument that other firms, like Microsoft and Amazon, are also participating doesn’t make this any less risky for Google. Google’s unique history, its motto Don’t Be Evil, and its direct reach into the lives of billions of users set it apart."

The letter asked Pichai to cancel the project and draft a policy that neither Google nor its contractors would build warfare technology.