The USA has sent a specially adapted nuclear-proof airplane from Andrews Airforce Base in Washington to RAF Mildenhall in the UK.
The Boeing 747 E4-B is fitted with nuclear and thermal shielding and is nicknamed both the Doomsday plane and the Flying Pentagon.
The plane, officially called Nightwatch, has steel-mesh reinforced windows and three decks of monitoring and communications equipment, and is a mobile war room and aerial command post - effectively a Situation Room in the sky.
Designed during the Cold War, the Nightwatch has three decks. It can hold a crew of 112 people and can fly for 12 hours without landing, – while aerial refuelling means it can stay in the air for days. Its windows are reported to have wire mesh to keep them intact, while equipment and wiring on board are hardened and there is thermal and nuclear shielding in the event of a blast.
Inside, it has 18 bunks and six bathrooms, a briefing room, conference room, work areas and executive quarters – but unlike Air Force One the décor is said to be functional, befitting its military role. The bubble on the top is called a “ray dome” or “radome” and contains dozens of satellite dishes and antennae which can communicate with any US ship, submarine or aircraft anywhere in the world.
Washington has maintained a fleet of Nightwatch command-and-control Boeing 747 E4-B aircraft since the 70s, with the specific purpose of providing an airborne base for the US defence secretary and senior military personnel to conduct operations during a war.
The aircraft can remain in the air for days and is designed to withstand the electromagnetic pulse from a nuclear blast. It conducts routine training and readiness missions. At least one E4-B is kept on 24/7 readiness.
The plane has been sent as the war in Ukraine continues.