Defence secretary Michael Fallon said he would “not give any details” on the Trident nuclear missile system as he stood before the Commons today

MPs and campaigners accused the government of covering up a failed Trident missile test weeks before a crucial parliamentary renewal vote.

The MP added the effectiveness of the UK’s independent nuclear deterrent was “not in doubt” after Speaker John Bercow granted an urgent question on Trident from Labour’s former defence minister Kevan Jones.

The Sunday Times revealed yesterday that an unarmed Trident D5 missile veered off course after being launched from the coast of Florida, in June last year.

It happened only weeks before Theresa May became Prime Minister and held a crucial vote on the renewal of Trident, which passed the commons and could cost up to £40 billion.

It remains unclear whether or not Mrs May was aware that the test failed, but a Downing Street official confirmed today that she had been briefed on the launch.

After a much publicised debate which lasted five hours, MPs voted 472 to 117 to renew the program, though it was opposed by all SNP members as well as leader of the Labour party, Jeremy Corbyn.

The shadow defence minister, Nia Griffith, called the revelation of the cover-up a “very embarrassing situation” and senior Tory MPs have called for the sacking of officials who authorised the media blackout on the missile launch, past episodes of which were publicised in 2000, 2005, 2009 and 2012.

The Prime Minister came under pressure to comment on whether she was aware of the launch yesterday, though dodged repeated questioning during an appearance on BBC’s The Andrew Marr Show.

The Scottish National Party’s Westminster leader, Angus Robertson MP, told Sky News: “The Prime Minister must come to Parliament this week and outline exactly what she knew – and when – about this reported malfunction and alleged UK government cover up.

“It would be utterly unacceptable, and deeply serious, if it turns out that this information was deliberately kept from MPs at the time of the renewal vote for the Trident weapons of mass destruction programme.”

Julian Lewis MP, the chair of the defence select committee and a Tory backbencher, blamed the Cameron administration for “playing politics” with the nuclear deterrent programme.

“The people who should’ve been clear about it were the people who were in control of the government at the time when this test-fire took place in June,” said Lewis.