Three of Britain's Four Nuclear Deterrent Submarines Are at Sea for the First Time in Five Years

Three of the United Kingdom's four nuclear deterrent submarines are at sea at the same time for the first time in five years, The Times reported on Wednesday. The newspaper said at least one of the vessels is armed with ballistic missiles carrying nuclear warheads.

The report identified the submarines at sea as HMS Vanguard, HMS Vigilant and HMS Vengeance, all part of the Vanguard class. The fourth boat, HMS Victorious, is currently undergoing maintenance. A navy source quoted by The Times called the deployment "unusual" but gave no further detail.

Under normal practice, the UK keeps at least one of the four submarines on patrol at all times as a security guarantee. Navy Lookout, an independent publication covering the Royal Navy, says a missile-carrying submarine has been at sea without a break since 1969. It said the second vessel is believed to be preparing to relieve the boat on patrol, while the third is likely carrying out sea trials or work-up activity.

Long patrols are not new. Last year HMS Vanguard spent 200 days at sea, a week short of the longest known submarine deployment of 207 days, which HMS Victorious completed in 2021.

The deployment has prompted questions over whether Britain has shifted its defence posture. Defence Secretary Wes Streeting warned last week that the country should be prepared for war. Writing in the Telegraph on Saturday, Streeting said Britain must be ready within 1,000 days. "By 2030, their force strength and war economy could put them in a position to attack," he wrote, adding that the government would ensure the mission is accomplished.

According to Sky News, a defence ministry spokesperson described the nuclear deterrent as the "cornerstone of our national security, protecting the UK and our NATO allies every moment of every day". The spokesperson added that the UK remains the only European ally to commit its nuclear deterrent to NATO's defence, so all allies already benefit from it.

Last week, British and French fighter jets also took part in their first joint exercise involving France's airborne nuclear capability. The French armed forces ministry said RAF Typhoon fighters escorted French jets while simulating a nuclear strike. French Armed Forces Minister Catherine Vautrin said having "independent nuclear forces does not preclude coordination", and that nuclear cooperation with the UK continues to deepen.

Streeting said that in an "increasingly dangerous world, our adversaries should be in no doubt", and that the UK and France stand together in their commitment to European security.

The warnings follow the launch last week of the government's "Be Ready" campaign. It urges households to keep three days' supply of tinned food and bottled water, cash and a wind-up radio in case a cyberattack or severe weather disrupts infrastructure. They also come after reports that Russia has been using fishing trawlers to track and spy on the UK's undersea cables.