Synthesia makes digital presenters for clients to use in corporate videos and counts 70% of FTSE 100 as customers

A British AI startup that makes realistic video avatars has almost doubled its valuation to $4bn (£3bn), in a boost for the UK technology sector.

Synthesia was valued at $2.1bn last year and moved into new offices in central London, marking the moment with a ceremony attended by the Sadiq Khan, the city’s mayor, and Peter Kyle, then technology secretary.

On Monday, it announced its latest funding round, led by an existing investor, Google Ventures, had raised $200m and valued the British company at $4bn. Google Ventures is the search firm’s venture capital arm.

Synthesia uses human actors to generate digital avatars of people and also offers employers the ability to create replicas of their staff. Those avatars are then deployed by organisations in corporate videos in a range of scenarios such as health and safety in the workplace, advising on cybersecurity and how to communicate better at work.