How UK's top Trident officials met three days before indyref

A list of meetings disclosed under freedom of information law also reveals that two days later on the eve of the referendum, one of the officials met with a senior policy advisor to Prime Minister David Cameron at Downing Street.

The revelations have been seized on by the Scottish National Party (SNP) as evidence that Westminster did consider the fate of the Trident nuclear weapons system in the event of a Yes vote - something that the MoD has always denied. SNP policy was to rid Scotland of Trident as soon as possible after independence.

The SNP's interpretation has been backed by a leading academic and campaigners, but it is strongly disputed by the MoD. The meetings were "routine" and "not referendum related", the MoD insisted.

The MoD has released a list of meetings attended by its chief of defence materiel [correct: not material], Bernard Gray, during 2014. On 15 September he met for an hour with three senior nuclear officials: Rear Admiral Mark Beverstock, director of chief strategic systems executive; Andrew Mackinder, strategic weapons head; and Rear Admiral Mike Wareham, submarines director.

Also present was Joseph Hubback, an assistant principal with the US management consultants McKinsey. All the MoD said about the purpose of the meeting was that it covered "maritime programme shaping".

According to the list, Gray had no other meetings in 2014 covering the same topic or involving the same three MoD officials. It was the only meeting listed involving Beverstock, who plays a key role in maintaining the submarine-launched nuclear-armed Trident missiles based on the Clyde.

The next meeting listed for Gray was for an hour on 17 September with Conrad Bailey, a senior policy advisor at 10 Downing Street. The purpose of that meeting, according to the MoD, was "not recorded".

Gray also met with US President George W. Bush's former special assistant and defence consultant, Frank Miller, on 4 September. On the 9 September Miller, an enthusiastic supporter of Trident, was quoted warning that the SNP could force the UK to abandon nuclear weapons and isolate the US.

The SNP's Westminster leader and defence spokesperson, Angus Robertson MP, argued that the timing, participants and topic of the meeting on 15 September meant that it wasn't routine. "The fact that these four had not met in the previous nine months just adds substance," he said.

"Compounded with the fact that just one day before the referendum Gray met Number 10's senior policy advisor suggests at the prime ministerial level the need to remove Trident following the referendum might have been regarded as a real possibility."

Robertson stressed that Trident was "redundant and obscene" and the SNP wanted rid of it. "No one in their right minds believes the MoD did not then - and does not now - have a plan to move its nuclear arsenal should the need arise," he told the Sunday Herald.

According to William Walker, emeritus professor of international relations at the University of St Andrews, it was impossible to know for sure what was discussed. "But the timing and those involved do suggest that Trident's fate after the referendum would have been on the agenda," he said.

"The MoD was understandably nervous when opinion polls narrowed. It would be surprising if they avoided the subject."

John Ainslie, coordinator of the Scottish Campaign for Nuclear Disarmament, thought the future of Trident was discussed. "If you were a fly on the wall you would probably have heard these Whitehall mandarins panicking about what a Yes vote would mean for Britain's nuclear forces," he said.

"It is inconceivable that they could have avoided this central question three days before the referendum."

The MoD, however, stressed that the meetings were no more than regular catch-ups. "These routine meetings were not referendum related and any suggestion they were is false," said an MoD spokeswoman.

"We made no plans for Scottish independence because the government was and is clear that Scotland is safer and better defended as part of the UK, protected by the full range of UK defence capabilities, and benefitting from the manpower, bases and military equipment that the union provides."

The MoD believes that the nuclear deterrent is the ultimate guarantor of the UK's security, and no alternative would be as effective. There were never any plans to move Trident from the Clyde, and the facilities there could not be replicated elsewhere without a vast cost to taxpayers, it says.