Facebook is set to double its UK office capacity by investing in two new buildings in King's Cross, significantly bulking up the Silicon Valley tech giant's presence in London.

The social network company said the new buildings would boost its capacity to up to 6,000 staff and workers in the UK, although it would not confirm how many new jobs will follow as a result. The new offices have yet to be built but Facebook said the space would be ready by 2021.

Facebook has already been scaling up its UK presence with a new London site that is said would create 800 new jobs in December last year. By the end of 2018, Facebook will have 2,300 staff in the UK.

Some of its new business ventures have been developed in the UK, including Workplace, its human resources tool, while Facebook also has a London-based virtual reality team working on its Oculus headset.

The new offices will include 600,000sq ft of space in King's Cross joining search giant Google, which has received permission for 1m sq ft of office space for its new £1bn UK headquarters.

Digital secretary Jeremy Wright QC said the expansion planned by Facebook was "another vote of confidence in our economy" and would help the UK secure "high-paying, high-skilled jobs of the future".