Construction workers on Friday were putting the finishing touches on the United States’ new Embassy in the United Kingdom, situated on the south bank of the River Thames in London, as captured by an epa photojournalist.

Scheduled to open in a month’s time, with some media saying that the inauguration could be made by President Donald Trump himself, the 12-story cube-like building reportedly cost $1 billion, the most expensive US embassy to date.

“This is a process that will produce a modern, welcoming, safe and energy efficient embassy for the 21st century,” the US legation and consulate website said.

Ambassador to the UK Robert "Woody" Johnson, who showed journalists around the building just to the east of Battersea Park on Wednesday, declined to comment on whether Trump would be the one to open the gleaming new premises.

“We look forward to welcoming him,” Johnson said, adding that “no date is set.” Johnson said Trump was “a busy president.”

The ambassador is the owner of the New York Jets football team and also a personal friend of the president.

The glass cube was designed by US architect Kieran Timberlake, whose brief was to create an embassy that gave an impression of openness while at the same time concealing its modern means of defending itself from attacks.

The building is set some 30 meters (100 feet) back from the street and has a moat, like medieval castles used to, waterfalls and deep trenches designed to stop even a determined truck bomber.

To make extra sure, the design also includes a thick blast wall.

The cube is also designed to generate more energy than it consumes and has a roof packed with solar panels.

Heat and sound insulation are also state of the art, according to Johnson.

Journalists were curious to see where the CIA’s listening posts were located, but that was not something included in Johnson’s tour.