Who holds Britain's nuclear button when Prime Minister Johnson falls ill?

British Prime Minister Boris Johnson. Photo: Reuters

According to Reuters, the British Prime Minister remained in intensive care on April 7 after receiving oxygen support due to serious complications from Covid-19. Mr. Johnson's personal "battle" with the virus has affected the British Government as the country is considered by scientists to be entering one of the deadliest weeks of the pandemic. To date, Covid-19 has caused 5,373 deaths in the UK.

As previously reported by the media, Mr Johnson, 55, was admitted to St Thomas' Hospital on the night of April 5 after more than 10 days of showing no signs of improvement in his coronavirus symptoms, including a high fever and cough. His condition rapidly worsened over the next 24 hours and he was transferred to the intensive care unit, where the most critical cases are treated. Although he required oxygen, his office said on April 6 that Johnson was conscious and was transferred to the intensive care unit as a precaution against needing a ventilator.

“He is not on a ventilator at the moment. He is on a little oxygen and he is obviously being closely monitored. He is in the intensive care unit, being looked after by his medical team, being looked after very well at St Thomas’ Hospital,” Chief Cabinet Secretary Michael Gove told LBC radio on 7 April.

Mr Johnson is now the first leader of a major power to be hospitalised with Covid-19. Downing Street said the British Prime Minister had asked Foreign Secretary Dominic Raab to represent him “where necessary”.

Asked whether Raab had been given the nuclear codes while Mr Johnson was in hospital, Mr Gove said: “There are very well-established procedures that we have in place. I can’t really speak on national security issues.”

The UK is one of only five official nuclear weapons states in the world, and has four nuclear submarines equipped with Trident II D5 ballistic missiles carrying nuclear warheads. The UK has a stockpile of around 215 nuclear warheads, although only around 120 are operational.

Only the British Prime Minister can order a nuclear attack. This order must be transmitted to one of Britain's nuclear-powered ships via a special code sequence.