Scottish Nationalists were right to be concerned about the role of British security services in last year's independence referendum, according to fugitive Wikileaks founder Julian Assange.

The Australian expert in espionage believes independence amounted to a "national security threat" to the UK, justifying the mobilisation of the "full capacities" of the British state's surveillance network.

Some Scottish Nationalists, most notably former SNP deputy leader Jim Sillars, have long warned that British intelligence agencies have taken an interest in them.

Speaking via a video link from his bolthole in London's Ecuadorian Embassy, Mr Assange said they had good reasons to do so.

Asked by The Herald if Scottish nationalists were paranoid to think security services were involved in the referendum, he said: "No, they are not at all paranoid."

He added: "They are correct for a number of reasons.

"The attitude of the UK Government is that this is a national security issue, that Scottish independence is, in effect, a threat to the state.

"This mean that the full capacities of the GCHQ, for example, could be deployed."

The journalist and IT expert cited The Herald's revelations that the UK Government had sought support from foreign governments against independence as evidence of how seriously Britain took the threat of independence.

He referred to resulting foreign critics of independence, such as former Swedish foreign secretary Carl Bildt, as a "cast of characters" associated with US and UK interests.

Mr Assange also cited the Treasury's partisan position on independence as evidence that the referendum was not politics as usual.

MPs last month have found that civil servants - in the Treasury and Holyrood - had "compromised their impartiality" during the referendum.

The campaigner, however, warned that it would not have been easy for GCHQ - which operates a major surveillance operation from its base in England - or other bodies to spy on Scottish nationalists.

He said: "There are many Scots employed in these agencies. So care has to be undertaken because Scots in those agencies may well reveal what is being done.

"As they did reveal that information from the FCO going out across the world to lobby other states to influence the result."

Unionist figures traditionally dismiss suggestions of involvement in the independence referendum by GCHQ or MI5 as "nationalist paranoia", saying the security services have more important threats to deal with, such as Islamist terror groups.

Mr Assange was speaking to an audience of some 400 international lawyers at the Commonwealth Law Conference at the SECC in Glasgow.

His talk mostly focused on how lawyers protected their communications with clients from security services after the UK and the US revealed policies of mass interceptions of emails.

Mr Assange, a journalist and expert in IT encryption, is wanted for espionage in the United States after his Wikileaks website published huge quantities of confidential information about the UK, US and other countries, including their role in conflicts in Afghanistan and Iraq.

He is also wanted for questioning in Sweden over allegations of sex offences, which he denies.

The 43-year-old has been hold up in the Ecuadorian mission for more than 1000 days. Asked how he was, he said this subject was "off topic". However, he looked well, with his trademark white hair combed back and his beard neatly trimmed.