Billionaire property investors David and Simon Reuben won approval to turn one of the oldest office towers in London’s Westminster borough into luxury apartments.

The brothers will be allowed to turn the Millbank Tower complex near the Palace of Westminster into 207 homes with a skybar and a 150-bedroom hotel, the borough council decided at a meeting Tuesday.

Soaring prices for luxury homes encouraged developers to seek to turn office space into 16,600 new homes in greater London in the two years through May 2015. Falling demand, rising supply and an increase in office rents is causing some developers to reconsider plans for homes, consulting firm Arcadis NV said on Monday.

Average home values rose 9.7 percent in the U.K. capital to 524,000 pounds ($746,333) in the 12 months through February, the Office for National Statistics said on Tuesday. The house price index fell 2.8 percent in February from January, the data show.

The tower housed the U.K.’s Labour Party when former Prime Minister Tony Blair won the 1997 national election.