[1] Pevsner notes that the architectural form of Portland House was influenced by the Pirelli Tower (1955–58) in Milan by architect Gio Ponti.
Firms that have at one point occupied Portland House for office space include American Express, Crossrail, HomeAway UK, Owners Direct, Direct Ferries Orbus Software, Increase the Wedge, NetBooster, Somo Global, TradeDoubler, Wunder2, uSwitch, Upmystreet.com, Reef Television, Rentokil Initial, AkzoNobel, Monica Vinader and IWG.
The ground floor has a portico arrangement of pillars which reflect the octagonal cross-section of the building.
The Portland House is substantially similar in design to the MetLife Building in New York City.
As of June 2021, the building is entirely vacant, with the ground floor behind hoardings, pending renovation by Land Securities.