PRIME minster Theresa May was informed about a recent test of the Trident nuclear deterrent when she came into office last year, Downing Street has said.

But the PM's official spokeswoman declined to confirm or deny reports that a missile malfunctioned during the test, stating only that Mrs May was told the operation was completed successfully.

Mrs May refused to answer questions on Sunday over her knowledge of the test, in which an unarmed Trident missile reportedly veered off course off the coast of Florida in June.

Watch Mrs May evade questions on the Andrew Marr Show:

But her official spokeswoman has now told reporters that the PM was briefed on the "demonstration and shakedown" operation undertaken by HMS Vengeance on its return to service following a refit.

The PM was informed that the operation was successful, allowing Vengeance and its crew to return to service.

The spokeswoman told a regular Westminster media briefing that, as a matter of long-standing policy, the Government did not publicly discuss the operational detail of exercises of this type.

This new information comes after mounting pressure from MPs, including John Woodcock, for Mrs May to "come clean" on what she knew.

Yesterday, Mr Woodcock said: "I think the prime minister and the rest of her government needs to stop being evasive about this issue, and to come clean about what they knew, and when and why they chose not to put the facts in the public domain."

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Read more about the outcry over these revelations over Trident