GEORGE Robertson, the NATO secretary general, is considering legal action against the owners of the Sunday Herald, over internet allegations about his connection to Thomas Hamilton, the Dunblane killer.

The move by Lord Robertson, which could force Scottish Media Group to pay out hundreds of thousands of pounds in compensation, follows claims posted on the newspaper’s discussion page by a member of the public.

Last night, lawyers warned that the scale of the payout could even force the Sunday Herald out of business, given worldwide awareness of the Dunblane massacre.

There was also concern that the case could have serious implications for anyone who operates a website encouraging views from members of the public.

Andrew Jaspan, the editor of the Glasgow-based Sunday Herald, admitted the website was not "policed", although he insisted the offending material had been removed half an hour after the paper was contacted by Lord Robertson’s representatives.

However, last night, a legal source said the information posted on the Sunday Herald forum had been there for four weeks and could have badly damaged Lord Robertson’s reputation.

He said: "We are talking about a well-known public figure on the international stage being linked through these allegations to an atrocity which is known throughout the world.

"We are talking about hundreds of thousands of pounds in compensation and even an amount which could close the newspaper.

"Authors already have a responsibility not to publish defamatory statements. If they do, and they do put them on the web, then there is no reason why they shouldn’t be liable worldwide."

Another Scottish legal expert said online defamation typified by the case involving Lord Robertson was an area of increasing concern for businesses.

Traditionally, defamation has been considered a national matter, with little scope for conflict between laws of different countries, but the internet has muddied the waters by emphasising the cross-border access to websites which is possible for users.

Gillian Davies, a solicitor with Edinburgh-based Shepherd & Wedderburn, who specialise in intellectual property and information technology law, said: "Documents published and uploaded in one country can be viewed and downloaded all over the world, exposing newspapers and other publishers to the libel laws of potentially any nation which provides internet access to its citizens.

"The lack of a uniform approach at an international level to such issues prevents any kind of legal certainty."

Internet speculation about Lord Robertson grew following the revelation that 106 documents were closed to the public after the inquiry into the shootings at Dunblane Primary School in 1996.

Lord Robertson told Lord Cullen’s public inquiry he became increasingly concerned about Hamilton’s militaristic camps after his own son attended Dunblane Rovers, run by Hamilton in 1983. After speaking of his fears to Michael Forsyth, then a newly elected MP for Stirling, Lord Robertson kept him informed of publicity relating to Hamilton’s clubs.

Yesterday, the Mail on Sunday claimed the letters between the two politicians drew a detailed picture of Hamilton’s perverted behaviour towards young boys in his care as well as his firearms obsession.

The paper states that letters from Mr Forsyth "campaigned on behalf" of Hamilton from 1983 onwards, but that he also passed to police parental concerns about Hamilton’s personality. After receiving letters from Hamilton complaining about a police investigation into his 1988 summer camp, Mr Forsyth raised the issue with Central Scotland Police.

A year later, Hamilton met the force’s deputy chief constable and, the Mail says, shortly afterwards the killer wrote to Mr Forsyth "thanking him for his assistance".