Michael Fallon has rejected a call for "greater transparency" from the government over the UK's nuclear deterrent, as he faced a grilling from MPs in the House of Commons on 23 January.

The evasive defence secretary also dodged numerous questions relating to an alleged cover-up of a failed Trident missile test in June.

"There are very few things that we cannot discuss openly in parliament, but the security of our nuclear deterrent is certainly one of them," Fallon said.

But the top Conservative did reveal that the submarine involved in the operation returned to Trident's operation cycle and confirmed that Theresa May knew about the test.

"The details of the demonstration and shakedown operation I'm not going to discuss publicly on the floor of this House," Fallon told MPs.

"All I can do is repeat that HMS Vengeance has successfully been certified again to re-join the operation cycle.

"I've made it very clear that the previous prime minister and this prime minister were of course informed about the maintenance of the nuclear deterrent and the outcome of the test and the successful return of HMS Vengeance to the operational cycle."

The statement, in response to an urgent question from Labour's shadow defence minister Kevan Jones, comes after The Sunday Times claimed the unarmed missile veered off towards the Florida mainland.

Jones repeatedly refused to answer questions about the missile, while CNN News claimed the missile was diverted into the sea as part of a self-destruct mechanism.

The incident, under David Cameron's watch as prime minister, happened just weeks before a House of Commons vote on the renewal of the nuclear weapons system.