IWG has agreed to let all of 25 Wilton Street, SW1, from Royal London for its Spaces brand.
Opposite Victoria Station, the recently revamped building provides 80,000 sq ft of offices, which IWG is understood to have taken on a 15-year lease for around £65 per sq ft.
Spaces was acquired by IWG, then known as Regus, in 2015 and currently operates out of eight locations across central London.