The US Embassy in London is to be converted into a luxury hotel by Qatari-backed investors.

The building is to be redeveloped into a 137-room hotel complete with shops, restaurants, a spa and a 1,000-capacity ballroom.

The development, proposed by Qatar’s state-owned real estate company Qatar Diar, is set to start next year when embassy staff relocate from the building in Grosvenor Square to a new embassy being built in Wandsworth.

There are also plans to remove security bollards, fences and gates which were erected in front of the building following the 9/11 attacks.

Westminster Council approved the conversion of the embassy in Mayfair.