Buffered by an 8ft-deep, crescent-shaped moat and surrounded by armed guards, London’s new US embassy appears like Fort Knox amid a tangle of cranes and construction work.

But as it opened for previews, the architects said they hope that this building will be welcoming and open. There is no perimeter fence; instead, it hides its might by discreetly disguising security measures, such as bollards camouflaged by plants.

Ambassador Woody Johnson, who has been in the job for just three months, said that the new embassy represented “a signal to the world that this special relationship that we have is stronger and is going to grow and get better.”

He added that President Trump “mentioned that to me himself ... He said 'I want you to make it stronger', and I intend to do that if I can."