The British government confirmed on Wednesday that the test launch of an unarmed Trident missile from a Royal Navy submarine last month had failed, raising questions about the state of Britain’s nuclear deterrence capability.
It was the second straight malfunction of such a launch, coming nearly eight years after another Trident flew off course at sea, an incident that at the time drew criticism about the government’s failure to disclose it.
This time, too, the failed launch was first reported not by the defense ministry but by a London tabloid, The Sun, which said the missile’s boosters failed and it landed in the water not far from the submarine, the H.M.S. Vanguard, which had just come out of a seven-year refurbishment.
Britain’s defense secretary, Grant Shapps, and the top-ranking officer in the Royal Navy were both aboard the Vanguard for the test on Jan. 30. In a written statement to the House of Commons, Mr. Shapps said “an anomaly did occur” during the test launch but that it was “event specific.”
“There are no implications for the reliability of the wider Trident missile systems and stockpiles,” Mr. Shapps wrote. “Nor are there any implications for our ability to fire our nuclear weapons, should the circumstances arise in which we need to do so.”
Britain’s Navy has suffered a string of problems in recent months with its fleet. One of its flagship aircraft carriers, the H.MS. Queen Elizabeth, pulled out of a deployment to a NATO exercise off the coast of Norway earlier this month because of a problem with one of its propeller shafts.
Its sister ship, the H.M.S. Prince of Wales, took its place in the exercise, but its deployment was briefly delayed as well before it departed on Feb. 12. In 2022, the Prince of Wales broke down off the Isle of Wight, also because of a propeller-related issue, and required nine months of repairs.
Military analysts said it was difficult to say exactly what went wrong with the latest launch. Britain has four nuclear-powered submarines equipped with the Trident missile system, which is manufactured by the American firm Lockheed Martin. The missile was not armed with a nuclear warhead during the test.
“Whether the problem can now be rectified, or even what it is, is not clear,” said Malcolm Chalmers, the deputy director general of the Royal United Services Institute, a think tank in London. “But Vanguard is getting very old, beyond its planned service life, and it just came out of a seven-year repair and refueling.”
Mr. Chalmers criticized the government’s handling of the incident, noting that it had announced the test in advance but then failed to report its failure.
“Someone was bound to spot this, sooner or later,” he said, “and they should have got out in front of the story.”
The last failed launch, in June 2016, became a political headache for the government of Prime Minister Theresa May when news of it first leaked out several months later. Ms. May was initially unwilling to acknowledge the incident, even as she appealed to Parliament to invest in new Trident-armed submarines.
With anxieties rising about an aggressive Russia under President Vladimir V. Putin, Britain’s military readiness has again become a political hot button. The opposition Labour Party has accused successive Conservative-led governments of bleeding the armed forces through years of budget cuts imposed by fiscal austerity.
“Over the last 13 years, our army has been cut to the smallest size since the days of Napoleon,” Labour’s lawmaker responsible for defense policy, John Healey, and the party’s chief foreign policy official, David Lammy, wrote in a column last fall in the Daily Telegraph.
