THE SNP was spied on by British secret service agents, previously classified Government files seen by Scotland on Sunday have finally proved.
Claims of surveillance of nationalist politicians by intelligence officers have circulated for years, but the new papers provide the first incontrovertible evidence that the state spied on the SNP in the 1950s.
Agents from MI5 and Special Branch infiltrated the party as part of a campaign to undermine support for Scottish independence, the papers show.
The revelations have put First Minister Alex Salmond - who in opposition complained about closed Government files on the SNP - under pressure to close a legal loophole that allows the secret services to intercept the calls of Scottish parliamentarians.
The files, which have been opened and placed in the UK National Archives in Kew, show that throughout the 1950s Special Branch officers posed as nationalist supporters and attended party meetings and rallies.
The dossiers contain first-hand accounts from numerous unnamed agents of party meetings, and also include names of SNP members and sympathisers. They also provided transcripts of speeches and give particular attention to members they believed were on the more radical and militant wing of the party.
The dozens of documents also contain the remarkable claim that Dr Robert McIntyre, the then SNP leader, wanted Scotland to pull out of the UK and apply to be the 49th state of the USA.
A number of present-day MSPs, including former SNP leadership contender Alex Neil, claim MI5 still monitors pro-independence politicians and may even have stepped up surveillance since the Nationalists won power in May.
So far the new SNP administration has rejected calls to extend the "Wilson Doctrine" - which bans the secret services from tapping the phones of MPs - to Holyrood.
Alex Neil, deputy convener of Holyrood's European and External Relations Committee, said: "It does not surprise me in the least to have it confirmed that the UK Government has used dirty tricks against the SNP in the past.
"I would certainly not discount the idea that the British state is still acting to undermine the SNP, especially given the substantial progress it has made recently.
"We need to get clear assurances from Westminster that nothing is being done to undermine the democratic wishes of the Scottish people."
Margo MacDonald, the independent nationalist MSP and former SNP deputy leader, added: "Scotland is strategically important and energy rich, and I think it would be extraordinary if the security services weren't taking a close interest in recent developments in Scotland.
Fellow SNP member Christine Grahame, convener of Holyrood's Health and Sport Committee, is disappointed that Justice Minister Kenny MacAskill has so far rejected her calls to outlaw the monitoring of MSPs' phone calls.
MacAskill said: "The Scottish Government has no plans to seek to extend the Wilson Doctrine to cover MSPs, nor to introduce a convention to prevent police Special Branches carrying out covert surveillance in circumstances that meet the strict tests of necessity required by law."
A spokesman for the Home Office, which deals with UK intelligence services, said: "We neither confirm nor deny operational matters."
A Scottish Government spokesman confirmed that the First Minister has the power to sign warrants to bug telephones in Scotland.
Files open on curious case of spooks, SNP and Idi Amin
THE SETTING was Hyde Park in the centre of London. The speaker was a young and charismatic politician who had broken the mould.
The crowd was mainly made up of his supporters who gathered to hear his views on self-rule, daring raids on the establishment and possible alliance with a foreign power.
Except for one. He was the "spook" from MI5 and he duly delivered his report on the enemy within - the Scottish National Party - to his political masters in Whitehall.
Scotland on Sunday can reveal today for the first time the official papers that prove that MI5 and Special Branch spied on the SNP during the 1950s because of fears over independence.
According to the documents lodged at the National Archives in Kew, government agents routinely attended party meetings to compile lists of SNP members and where they lived, focusing on the more militant individuals. They also provided detailed transcripts of speeches.
The files show that in April, 1951, a government agent attended the party gathering in Hyde Park to keep a close eye on party leader Robert McIntyre, who had made history by becoming the first SNP MP after winning a by-election in Motherwell six years earlier.
A detailed report on his remarks and conduct states: "Dr McIntyre said the party was a constitutional one, but as such it had been ignored by the English. It was only when unconstitutional methods, such as the removal of the Stone of Destiny from Westminster Abbey [in 1950], were used that this country become aware of Scotland's wish for self-rule.
"He thought that Scotland would in fact be better off as the 49th state of the United States, both from an economic and defence aspect."
This revelation is at odds with the SNP's stance as a predominantly left-of-centre party, which remained suspicious of the US brand of unfettered free-market capitalism. The files include detailed reports of a meeting held by the London branch of the SNP in Conway Hall, Holborn, on May 31, 1954.
It states: "Attached is a list of the present paid-up members of the Scottish National Party, a list of members from 1953 and a list of names and addresses taken from a 'contact book', which includes the names of people who have expressed their sympathy with the Party at meetings and rallies."
Another Special Branch member filed a report on an SNP rally that took place in Trafalgar Square on April 19, 1953.
It lists those who attended, including McIntyre, who died in 1998, and states: "All of the speeches were moderate in tone and no references were made to Coronation, but, as I have detailed, two of the speakers did briefly comment on the title of HM the Queen."
The files record that SNP members eventually became suspicious of government infiltration and proposed that all new members be vouched for by a regular member. The Special Branch agent recorded: "This was on the grounds that a Mr Douglas, who was well versed in politics and spoke well, was regarded as a police spy."
SNP elder statesman said they were "shocked" their suspicions had finally been confirmed.
William Wolfe, who joined the SNP in the late 1950s and led the party between 1969 and 1979, said: "We always suspected that the party was being infiltrated by government agents, but it is still shocking to have that suspicion finally confirmed.
"I remember one individual in particular who claimed he had spent many years in America before joining the party.
"Something about him just didn't add up and we all suspected he was some sort of government informer. A lot of us used to joke about having moles in our midst, but it now appears that it was no laughing matter."
Wolfe added: "It is quite, quite wrong for a legitimate and democratic party to be put under surveillance in this way. I have absolutely no doubt that the UK Government will have several files on me, but I have nothing to hide."
Wolfe, 83, insists he was put under surveillance by M15 as late as the 1970s after he received a bizarre telex from the Ugandan dictator Idi Amin offering support for Scottish independence.
"It was a very strange incident, but I had it confirmed from the police that it led to my phone being tapped."
Security experts said the Home Office would have considered the SNP a legitimate target for surveillance.
Terrorism expert Paul Wilkinson, professor of international relations at St Andrews University, said: "This was the era when the taking of the Stone of Destiny from Westminster Abbey had become a huge national issue. I'm sure there was concern in Westminster and Whitehall that there was a more militant wing within supporters of Scottish independence which posed a threat of illegal actions and it is the job of MI5 to monitor potential dangers of that kind."