Google’s parent company has ditched a longstanding principle and lifted a ban on artificial intelligence (AI) being used for developing weapons and surveillance tools.

Alphabet has rewritten its guidelines on how it will use AI, dropping a section which previously ruled out applications that were “likely to cause harm”.

In a blog post Google defended the change, arguing that businesses and democratic governments needed to work together on AI that “supports national security”.

Experts say AI could be widely deployed on the battlefield – though there are fears about its use too, particularly with regard to autonomous weapons systems.

In its blog, Google said democracies should lead in AI development, guided by what it called “core values” like freedom, equality and respect for human rights.

“And we believe that companies, governments and organisations sharing these values should work together to create AI that protects people, promotes global growth and supports national security,” it added

The blog – written by senior vice president James Manyika and Demis Hassabis, who leads the AI lab Google DeepMind – said the company’s original AI principles published in 2018 needed to be updated as the technology had evolved.

Awareness of the military potential of AI has grown recently.

In January, MP’s argued that the conflict in Ukraine had shown the technology “offers serious military advantage on the battlefield”

As AI becomes more widespread and sophisticated it would “change the way defence works, from the back office to the frontline,” Emma Lewell-Buck MP, who chaired a recent commons report into the UK military’s use of AI, wrote.

But there is debate among AI experts and professionals over how the powerful new technology should be governed in broad terms, how far commercial gains should be allowed to determine its direction, and how best to guard against risks for humanity in general.

There is also controversy around the use of AI on the battlefield and in surveillance technologies.

Concern is greatest over the potential for AI-powered weapons capable of taking lethal action autonomously, with campaigners arguing controls are urgently needed.

The Doomsday Clock – which symbolises how near humanity is to destruction – cited that concern in its latest assessment of the dangers mankind faces.

“Systems that incorporate artificial intelligence in military targeting have been used in Ukraine and the Middle East, and several countries are moving to integrate artificial intelligence into their militaries”, it said.

“Such efforts raise questions about the extent to which machines will be allowed to make military decisions—even decisions that could kill on a vast scale”, it added.

That sentiment has been echoed by Catherine Connolly of the organization Stop Killer Robots.

“The money that we’re seeing being poured into autonomous weapons and the use of things like AI targeting systems is extremely concerning,” she told the Guardian newspaper.

Originally, long before the current surge of interest in the ethics of AI, Google’s founders, Sergei Brin and Larry Page, said their motto for the firm was “don’t be evil”.

When the company was restructured under the name Alphabet Inc in 2015 the parent company switched to “Do the right thing”.

Since then Google staff have sometimes pushed back against the approach taken by their executives.

In 2018, the firm did not renew a contract for AI work with the US Pentagon following resignations and a petition signed by thousands of employees.

They feared “Project Maven” was the first step towards using artificial intelligence for lethal purposes.

The blog was published just ahead of Alphabet’s end of year financial report, showing results that were weaker than market expectations, and knocking back its share price.

That was despite a 10% rise in revenue from digital advertising, its biggest earner, boosted by US election spending.

In its earnings report the company said it would spend $75bn ($60bn) on AI projects this year, 29% more than Wall Street analysts had expected.

The company is investing in the infrastructure to run AI, AI research, and applications such as AI-powered search.