Ministers have been accused of covering up a failed test of the Trident nuclear deterrent weeks before a crucial Commons vote on the future of the submarine-launched missile system.

Labour former defence minister Kevan Jones has demanded an inquiry into claims that the launch of an unarmed Trident II D5 missile from a British submarine off the coast of Florida in June malfunctioned.

On Saturday it was reported the cause of the failure remained top secret but questions could be asked over the Government's failure to publicise the failed test weeks before MPs approved the £40 billion Trident renewal programme in July.