Scottish independence: Trident is "ticket to Nato" SCOTLAND could be forced to keep Trident nuclear weapons for up to 20 years after independence as the UK seeks out an alternative base, leading military experts have said. Trident nuclear weapons may have to remain in Scotland for up to 20 years after independence as the UK seeks out an alternative base, leading military experts have said. A hardline approach on the withdrawal of the submarine-based weapons from Faslane on the Clyde could see Scotland blocked from joining the Nato defence alliance after independence, the experts warned. The SNP Government has pledged to remove Trident if Scots vote Yes in next year's independence referendum. Although safety would be a priority, First Minister Alex Salmond has indicated he wants this done quickly. Concerns have emerged that there are no feasible alternatives to Scotland, with bases in Plymouth and Barrow requiring costly upgrades. However, a Scotsman conference on defence yesterday heard that a lengthy "phased period" of withdrawal from Scotland, lasting 15 to 20 years, would be a likely solution. Faslane could be used as a bargaining chip in post-referendum negotiations, with Scotland agreeing to keep the submarines on the Clyde in exchange for lucrative contracts to build UK warships after independence, it was suggested. Professor William Walker, international nuclear relations expert of St Andrews University, said a negotiated outcome would have to be reached. This could see the submarines gradually phased out and remain at Faslane for a "considerable length of time." Despite Nationalist qualms, it would be the "reasonable counter-position to take." He added: "If you are phasing out Faslane and Coulport, you're talking about ten, 15, 20 years probably." Faslane houses the Vanguard submarines, while nearby Coulport stores the warheads which arm the Trident missiles. Professor Malcolm Chalmers, of military think-tank the Royal United Services Institute, said the "most likely scenario" after independence is that there would be a "long-term basing arrangement for Trident." This would provide Scotland with a "ticket" into Nato and defence co-operation with the rest of the UK. "There would be pressure to rebase," he said. But I think if there were an agreement for the first 15 to 20 years for Trident basing in Scotland, then the issue of the jobs that are there right now and the additional jobs associated with the Astute deployment to Faslane, rising to 8,200 including service personnel by 2020, those jobs would be still be there. I guess at that point if that was happening, it's quite likely in the short term that other elements of UK defence employment in Scotland could remain as well - the RAF in Lossiemouth, maybe even UK army bases. Prof Chalmers said it would take the new independent Scottish defence force time to build air and maritime capability. He added: "Given the budgetary constraints an independent Scotland would face, they may welcome a very strong long-term UK commitment to supporting Scotland's maritime and air patrol. The UK itself wouldn't want to leave itself vulnerable, so there could be a surge of interest there, provided the Trident issue was solved. Former SNP defence spokesman Stuart Crawford - an ex-army captain - said a recent defence conference he attended on independence heard repeated concerns that if Scotland insisted on the withdrawal of nuclear weapons from its territory, then "the accession of an independent Scotland to Nato would either be blocked or would stretch out for some time." Professor Sir Hew Strachan, a military historian at Oxford University, said that was "very likely." Even if Scotland does not accept nuclear weapons within its territory, it would still be getting the "benefits from nuclear deterrents" as a Nato member, Prof Strachan added. "A principled opposition to nuclear weapons and then an aspiration to negotiate entry (to Nato) would be very difficult indeed," he added. Thousands of Scottish shipbuilding jobs rely on orders from the Royal Navy, including the aircraft carriers being assembled at Rosyth. The coalition government has indicated this would end if Scotland leaves the UK. Nations almost always buy equipment such as ships from home yards to boost employment and the local economy and this is exempt from the usual European Union procurement rules. Prof Chalmers indicated that the UK could still build the generation of Type 26 frigates on the Clyde - if a deal could be reached on keeping nuclear weapons in Scotland. A poll commissioned for former Tory party chairman Lord Ashcroft last month found that 51 per cent of people north of the Border want Trident replaced with an "equally powerful" nuclear missile system or a cheaper, more limited version. Only 34 per cent want to "give up nuclear weapons completely." An SNP spokesman said last night: "As Westminster's own Scottish affairs committee report concluded, it is possible to remove Trident from Scotland soon after independence. And the only way to remove these obscene - and obscenely expensive -weapons of mass destruction is to vote Yes next September. Military experts sat Scotland will need to "strike a deal" on defence with UK post-independence