Facebook has taken its London office footprint to more than 1M SF with a deal for a huge new office at King’s Cross Central, making it one of only seven occupiers to break the seven-figure mark.

The tech firm will pre-lease 611K SF across three buildings which will now be built at King’s Cross Central, housing 6,000 workers. The leasing deal highlights the scale of its growth plans for the U.K. — Facebook currently employs just 2,300 people here.

Staff at the new buildings will work on the Oculus Go virtual reality project and other projects, many of which will be based on artificial intelligence. The buildings will open in 2021.

Facebook occupies 88K SF at 10 Brock St. near Euston and 247K at Rathbone Place just off Oxford Street and, according to Estates Gazette, has agreed to take all of the 140K SF leased by WeWork at 125 Shaftesbury Ave. on a two-year deal, taking its total lease exposure to 1.1M SF.

That makes it the latest occupier in London to lease more than 1M SF of office space. Google will lease 1.4M SF when its own 1M SF office at King's Cross Central opens in 2019. Amazon is not far behind with 920K SF of London office space.

Tech firms are catching up with the banks that have typically been the largest private-sector occupiers of office space in London. Goldman Sachs is trimming its office footprint from 1.7M SF to 850K SF. Barclays and HSBC are keeping up the fight in banking, with 1.3M SF apiece, as is JP Morgan with 1M SF. Citi is the only other bank occupying more than 1M SF, but is looking to sublet some of its 1.1M SF at Canary Wharf.

When all of its offices open, WeWork will be the largest private-sector occupier in London with 2.6M SF and counting.

King’s Cross Central is being developed by Argent and the majority owner is AustralianSuper. Savills and Cushman & Wakefield provided leasing advice to the owners and BCLP provided legal advice.