The global tech company acquired Central Saint Giles from previous owners Legal & General and Mitsubishi, which had jointly owned the asset for over a decade.

Google said the deal “represents our continued confidence in the office as a place for in-person collaboration and connection”, adding that it will embark on a multi-million refurbishment of the Central Saint Giles offices over the next few years.

The colourful office, which was architect Renzo Piano’s first UK project, comprises 408,000 sq ft of office space with 25,000 sq ft of restaurants and cafes on the ground floor. The site is formed of three buildings surrounding a central, public piazza and has an in-use BREEAM ‘Excellent’ rating.

At the western end of the site, two residential buildings contain 109 private, affordable and social rent apartments. The long leasehold interests of the residential buildings continue to be owned and managed by the existing owners.

Ronan Harris, vice president and managing director of Google UK & Ireland, said: “Building on our long-term commitment to the UK, we are purchasing the Central Saint Giles development - the site many Googlers have long called home - for $1 bn (£762.5m). Our investment in this striking Renzo Piano-designed development in London’s thriving West End represents our continued confidence in the office as a place for in-person collaboration and connection.

“Across all our UK sites, Google will have capacity for 10,000 employees as we continue to commit to the UK’s growth and success. This includes our new King’s Cross development, which is under construction.”

Bill Hughes, head of real assets for LGIM, said: “The sale is a strong sign of continued demand for the highest quality central London office space. It represents an excellent outcome for our investors, derived from consistently high-quality asset management by our team over the past decade, to deliver on the business plan for Central Saint Giles.

“We are pleased to have concluded the deal off-market with Google, which knows the asset well and saw the potential to invest longer-term in an exceptional building.”

Yuichiro Shioda, managing director and chief executive of Mitsubishi Estate London, added: “Mitsubishi Estate London has been involved with Central Saint Giles since the development phase, and this sale is the culmination of one of our flagship projects.

“Its acquisition by Google, a company renowned for occupying only the very best buildings, is a fitting legacy for one of the West End’s most successful and recognisable developments. We remain committed to London offices, through new opportunities as well as existing schemes.”

Cushman & Wakefield acted for the Central Saint Giles Limited Partnership, Legal & General and Mitsubishi’s holding company for the asset. Google was represented by CBRE.