Emotionally responsive customer service avatars are to be developed from technology used to bring graphics stars like Lara Croft to life after its developers received a major US expansion investment boost.

Speech Graphics, the Edinburgh and California-based technology team behind the heroine's facial expressions in the new Shadow of the Tomb Raider video game, are turning their tech sights on the customer service sector following a £2 million investment from Archangels, the prominent business angels syndicate, Par Equity and Scottish Investment Bank.

The University of Edinburgh spin-out firm said it is targeting the sector’s "intelligent virtual assistant" market, which is expected to grow from $750m (£538m) to $12.3bn (£8.8bn) by 2024, from its base in the San Francisco Bay area.

It said its technology introduces an emotional connection currently lacking in existing artificial intelligence platforms used in customer service.

It plans to use the proceeds of the funding to build a software platform around its core technology which will allow the development community to create emotionally responsive avatars which can engage in real-time conversations with customers.

Michael Berger, co-founder of Speech Graphics along with Dr Gregor Hofer, said: “Speech is not just about lip sync, it’s also about energy and emotion in the voice that need to come across perfectly in the face."

Speech Graphics' technology has been used to make videos for stars including rapper Kanye West and the company currently works with global brands including Warner Brothers, Microsoft, Def Jam, Sony and Activision.