London's new American Embassy is the most expensive in world

The new American Embassy in London is the most expensive in the world and includes safety features like a small moat.

Coming at a cost of $1bn and months behind schedule, the new building will have a 100-foot moat on the riverside which is supposedly designed to withstand terrorist attacks, the Daily Mail reported.

The new US diplomatic outpost is being relocated from the swanky neighbourhood of Mayfair to a more industrial one, Nine Elms, on the South Bank of the Thames.

Peter Rees, the City of London’s former head of planning, told the New York Times this was akin to “moving from New York’s Upper East Side to New Jersey.”

The current embassy in Grosvenor Square has been the target of terrorist threats in the past and a nuisance to its wealthy neighbours, prompting one aristocrat - a countess named Anca Vidaeff - to stage a hunger strike in protest of it, according to the newspaper.

It also does not include features in the modernist, wavy glass cube design of the new building like a reportedly bomb-resistant exterior, anti-ram barriers, and a carbon neutral operation due to photovoltaic cells.

It would also be able to continue operation through any possible London power outages.

The US embassy says that traditional security measures like high perimeter walls are being eschewed for “a welcoming urban amenity, a park for the city that fuses the new embassy to the city of London. Alternatives to perimeter walls and fences are achieved through landscape design”.

Wandsworth Council has also approved the large development project called Embassy Gardens to be located in the same neighbourhood, including 2,000 new flats, a number of retail businesses and restaurants, a 100-room hotel, and playgrounds.

American architect firm Kieran Timberlake is involved in the design building.

The Dutch government is among other governments planning to move out of expensive central London to the Nine Elms area. The US government agreed to sell the existing embassy building in Mayfair to a Qatari real estate company that will likely turn it into a hotel.