AN independent Scotland would have to accept keeping Trident for more than ten years if it wanted to join Nato, a leading defence expert has warned. 

Professor Malcolm Chalmers, deputy director general of the Royal United Services Institute (RUSI), said if the Scottish Government pressed ahead with removing nuclear weapons according to the SNP’s current timetable of five years after a Yes vote the UK would veto Scotland’s Nato membership.

During a speech in Washington DC last week the First Minister said Vladimir Putin’s invasion of Ukraine had cemented her belief Scotland should join Nato after becoming independent.

“The events of the last three months have strengthened my conviction that this position is absolutely the right one,” Ms Sturgeon told attendees to the event at the Brookings Institution in the US capital.

“I am firm in my view that — coupled with a strong relationship with the UK — membership of the EU and of Nato will be cornerstones of an independent Scotland’s security policy.”

Professor Chalmers told The Herald on Sunday the new state’s membership would depend on whether the UK would approve it.

He said he didn’t believe the UK would if an independent Scotland insisted on scrapping Trident on the SNP’s current timetable - which is five years after a Yes vote.

“The UK cannot maintain its position as a nuclear weapons state at the moment without the Faslane base in Scotland,” said Professor Chalmers.

“Given enough time, they probably could construct a new nuclear base but it would [take] a decade or more. But during which Scotland would have to maintain a Trident base. 

“If Scotland applied to become a Nato member, which it would have to do as a new member, it has to have the agreement of all existing members.

“But most of all the consent of the UK. Most, if not all, Nato countries, will follow the lead of the UK in this regard. If the UK says yes, then everybody else would go along, but if the UK says no then that would be the end of it.”

He added that building an alternative nuclear submarine base in the UK - possibly in the south west of England - would be a “massive undertaking” and could not be done in five years. 

“It would be a negotiating issue and I think for Scotland it is a very strong bargaining card because if Scotland were to say ‘yes we will keep this thing for as long as it takes’ then the UK in that circumstance turn around and say ‘you can join Nato’. But the reverse is also true.”

Professor Chalmers’s intervention came as the SNP’s defence spokesman Stewart McDonald told the BBC that while an independent Scotland would have no permanent nuclear submarine bases in Scotland, it would allow visiting nuclear submarines into port.

His comments prompted anger among the SNP CND group.

“What Stewart said in a BBC interview on Wednesday is in direct contradiction to a key element of SNP defence policy,” said Bill Ramsay, the convener of SNP CND, which represents party members who are in CND.

He said signatories of the ICAN parliamentary pledge - which includes all SNP MSPs - endorse the terms of the Treaty on The Prohibition of Nuclear Weapons which prohibits allowing “any stationing, installation or deployment of any nuclear weapons or other nuclear explosive devices in its territory or at any place under its jurisdiction or control.”

Asked about allowing temporary visits by nuclear submarines, Professor Chalmers said the weapons would not come off the vessels and little maintenance of the submarines would be required during the visit.

“The nuclear weapons won’t be removed, the nuclear power reactor will not be serviced. Nobody is talking about a Scottish - or a UK base for that matter serving the [visiting] submarines.

“Coming into port, the sailors will be fed and no doubt would do some training, and have some rest and recreation. But I don’t think there would be anything sophisticated that would be required.The weapons would remain in the submarines.”

Stewart McDonald SNP MP said: “Following a vote for independence the Scottish Government will negotiate the removal of the UK’s nuclear weapons with the UK government in a responsible fashion.

“The commitment I give to the Scottish people, to the UK and to Nato allies, is that the process of removal will be orderly and driven by a commitment to safety and security.

“It clearly makes sense that an independent Scotland should be in Nato, no other security arrangement would offer Scotland the kind of guarantees that Nato affords, but we will aim to be a value added member - much like Sweden and Finland will be - and ensure we have the conventional capability and defence posture to fully share the burden of Euro-Atlantic security with our allies.”