Prime minister was told of apparent missile malfunction before she took office and parliament voted to renew nuclear system

Theresa May was told about the test of a Trident missile that reportedly misfired, less than a week before she held a House of Commons vote on renewing the £40bn nuclear system.

The prime minister’s spokeswoman insisted on Monday that the operation was successful because the submarine HMS Vengeance and its crew were “certified” afterwards.

How did the Trident test fail and what did Theresa May know? Read more

However, she repeatedly refused to deny reports that a serious malfunction occurred during the test, saying the government would not get into operational details.

The disclosure comes after May declined four times to say what she knew about the apparent error when interviewed on the BBC’s Andrew Marr Show on Sunday.

Labour has been granted an urgent question on the Trident test, meaning Michael Fallon, the defence secretary, will have to appear before MPs on Monday afternoon.

Downing Street is facing growing accusations of a cover-up as the prime minister stood up in the Commons to ask MPs to vote for the renewal of the Trident programme on 18 July without telling them about problems with the missile system.



In that debate, May said she would be willing to authorise a nuclear strike that could kill 100,000 people, as the Commons voted overwhelmingly to replace Britain’s Trident programme.

Downing Street insisted it was a longstanding policy not to comment on the operational detail of Trident tests, but there was publicity around similar ones in 2005, 2009 and 2012.

“There is not a set approach on whether the outcome of these operations are publicised. You shouldn’t read anything into it not being publicised,” May’s spokeswoman said.

She said the demonstration and shakedown operation, essentially an MOT, was undertaken by HMS Vengeance on its return to service following a refit. No 10 said the prime minister had been fully briefed on the test and informed that the operation was successful, allowing Vengeance and its crew to return to service with “absolute confidence” in its capabilities.

However, the Sunday Times reported that there was a serious malfunction with the firing of the unarmed missile, which was meant to head towards the west coast of Africa.

Asked whether she was disputing the facts of the story that the missile misfired, the spokeswoman said: “I am not going to get into operational details.”

Weeks after the test, and shortly after May replaced David Cameron as prime minister, MPs voted overwhelmingly to spend up to £40bn on renewing Trident.

May is facing growing discontent from senior Tories, Labour and the Scottish National party about the failure to disclose problems with the test before that vote.

Julian Lewis, the Tory chair of the defence committee, called for somebody to be sacked over the controversy.

Lewis told broadcasters: “This sort of event is not one you can play both ways. These tests are routine but infrequent in this country. Whenever they work, which is 99% of the time, film is released of them working, so whichever person decided they wanted to draw a veil over one that didn’t work should have been sacked. You have always got to assume that something like this will come out.



“This test went wrong in June when it was a question of David Cameron and his team being at No 10. They evidently decided to cover this matter up.

“The only way she could have disclosed this matter would have been to point the finger of accusation against her predecessor for covering it up. So a tricky situation, but on the whole I think if she did know – which she probably did – she should have spoken up.”

The idea of a cover-up was disputed by one of Cameron’s former aides, who said it was “entirely false” to suggest that Cameron’s media team tried to cover up the incident, arguing that they were “disappointed” that the MP would make the claim.

John Whittingdale, the former culture secretary, criticised May’s response to questions about the test. “I don’t know if they had discussed what line she should take but I suspect her apparent inability to answer was not the best answer,” he told Radio 4’s Westminster Hour.

Timeline

December 2015 HMS Vengeance, one of the UK’s four nuclear submarines, returns to sea in December after a £350m four-year refit.

Monday 20 June 2016 As the last part of a process of certification to allow HMS Vengeance to resume service, the submarine test-fired a Trident II D5 ballistic missile off the coast of Florida. It was aimed at the southern Atlantic off the coast of Africa but headed off in the opposite direction over the US. The test was aborted. In spite of the malfunction, HMS Vengeance is certified and resumes service in June.

Wednesday 13 July 2016 Theresa May becomes prime minister.

Monday 18 July 2016 Commons votes overwhelmingly to replace Britain’s Trident nuclear weapons programme after five-hour debate in which May tells MPs she would give the order to fire a nuclear missile if she had to. More than half of Labour MPs join Conservatives to pass it by a majority of 355. MPs were unaware of the failed missile test.

Monday 23 January 2017 Downing Street confirms May was briefed about the test before the Commons debate. Opposition MPs press for a Commons statement. The defence secretary, Michael Fallon, is to deliver one.