Sadiq Khan is to warn in a major speech that artificial intelligence (AI) could destroy swathes of jobs in London and “usher in a new era of mass unemployment” unless ministers act now.

In his annual Mansion House speech, the London mayor will say the capital is “at the sharpest edge of change” because of its reliance on white‑collar workers in the finance and creative industries, and professional services such as law, accounting, consulting and marketing.

The mayor will argue that “we have a moral, social and economic duty to act” to ensure that new jobs are created to replace those that will disappear, with entry‑level and junior jobs the first to go.

In the speech on Thursday night, Khan will highlight research that suggests 70 % of skills in the average job will have changed by 2030.

However, he also sees huge potential benefits from AI for public services and productivity across the economy.

When he addresses business leaders and bankers at Mansion House, the London mayor will say:

“AI could enable us to transform our public services, turbo‑charge productivity and tackle some of our most complex challenges,”

but, used recklessly, will “usher in a new era of mass unemployment”. He will warn that the impact on the labour market will be “nothing short of colossal”.

He will add that there is a clear choice:

“Seize the potential of AI and use it as a super‑power for positive transformation and creation or surrender to it and sit back and watch as it becomes a weapon of mass destruction of jobs.”

City Hall is launching a London taskforce on AI and the future of work, with expertise from the government, businesses and the AI sector, to assess the potential impact of the new technology on London’s jobs market. It will also offer free AI training for Londoners.

More than half of workers in London expect AI to affect their jobs in some way in the next 12 months, according to City Hall polling.

Across the UK, up to 3 million low‑skilled jobs in trades, machine operations and admin roles could disappear by 2035 because of automation and AI, a report by the charity National Foundation for Educational Research found in November.

“We can shape this next technological revolution and, if we are bold in our efforts, ensure AI makes us richer, not poorer, stronger, not weaker, more connected and more confident, and more capable of building a fairer, safer and more prosperous London for everyone,” Khan will say.

He will argue the UK and others have been too slow to respond to new technology in the past and that the growth of social media has led to a youth mental‑health crisis, a surge in online abuse and a dangerous rise in misinformation.

Separately, Susan Langley, mayor of the City of London, said on Thursday morning she had noticed that some finance workers were wary of coming to London from abroad because they worry about their safety.

She told BBC Radio 4’s Today programme:

“The City of London is one of the safest cities in the world. There’s this perception that you’re going to step out of your office and be swept away in a tsunami of crime.

It’s completely wrong. Competition for investment is really fierce at the moment, and I think any kind of unfounded negative sentiment that’s being pushed out there really risks undermining the UK on the global stage, and we just can’t let it happen.”