London is suffering a chronic shortage of talent exacerbated by tight migration laws for skilled overseas workers, according to Tech London Advocates (TLA).

In a survey of 172 members of the trade network 43% believed a lack of talent could threaten the sector’s growth in the British capital, with one in ten criticising immigration legislation.

Russ Shaw, founder of TLA, said: "Encouraging young people to study STEM (science, technology, engineering and maths) subjects and initiatives to encourage digital skills are important steps in the right direction, but we are calling on the government to review education and immigration legislation to fuel the long term growth of London’s most vibrant industry."

Among the companies questioned about recruitment were business information company DueDil, video marketing firm Unruly and SwiftKey, creators of a predictive texting app. The coalition numbers 600 members, a quarter of which were surveyed.

Sarah Wood, founder of Unruly, said: "A diverse team, with people of different ages, backgrounds and areas of expertise, is best placed to meet the challenges and opportunities of the new economy, the digital economy that’s so crucial to the growth of UK plc.

"In addition to nurturing homegrown talent, the Government needs to do more to reduce the cost, complexity and time taken to push through visa applications."

Ruth Barnett, head of communications at SwiftKey, highlighted the importance of hiring bilingual staff, particularly those fluent in Chinese and Japanese. She described finding such employees as "challenging", adding that the lengthy visa process alienated prospective candidates.

Dan Crow, CTO of Songkick, which provides bespoke live music news, said: "There is a deep pool of highly experienced people in Silicon Valley. We’ve managed to tempt a few of them to London, but we’ve also lost some very promising potential employees because it is so hard for Americans to get work visas for the UK."