A leading US technology and life sciences firm with clients including Google, Facebook and LinkedIn has expanded into Europe with today’s opening of a London office.

Cooley announced what it claims to be ‘one of the largest ever US law firm arrivals’.

Chief executive officer Joe Conroy (pictured) said: ‘From our San Francisco and Silicon Valley roots, we have grown to 850 lawyers, solving complex business and litigation issues for the world’s most dynamic companies.’

The new office will be led by Justin Stock, former head of Morrison & Foerster’s London corporate practice.

As a US liaison partner, Ryan Naftulin, vice-chair of the firm’s business department and partner in charge of its Washington DC office, will focus on office integration and building ‘opportunistic growth’.

Cooley, which had a 2013 revenue of £445m, has 850 lawyers across 12 offices in the US, China and now Europe.