THE SNP's former deputy leader has said he is "ashamed" of unfairness in Scottish society and warned his own party that it is at risk of morphing into the establishment.

Jim Sillars spoke out as the headline act at a campaign launch for RISE, when he urged pro-independence voters and fellow party members to ignore the official 'both voters SNP' mantra and instead back the new left-wing alliance with their second ballot.

At the event in Edinburgh, he endorsed lead Glasgow RISE candidate Cat Boyd as the next Mhairi Black, the student turned MP who has become a darling of the independence movement since defeating the shadow foreign secretary last year.

Mr Sillars sat on a stage alongside a series of RISE candidates including Colin Fox, looking on as the former socialist MSP launched a stinging attack on "managerial" SNP approach to government and accusing the nationalists of pandering to the rich with its tax plans. He watched as Mr Fox directly criticised SNP members, saying they were "too easily browbeaten by loyalty tests".

Asked after the event if he agreed with RISE speakers who had suggested the SNP had become the party of the establishment, Mr Sillars said: "I think there's a danger of that. You're bound to be in a position after all these years in government that you take the governmental view, it happens to everybody, it's not that the SNP is particularly wicked. It's a natural progression that you tend to become governmental and managerial."

He also accused his party of going soft on independence, saying a pledge from RISE to table a resolution at Holyrood asserting the right of the Scottish Parliament to call a second referendum would force the SNP to take a stronger position.

In his speech, he said: "At the moment the SNP leadership on the independence referendum are saying mibbes aye, mibbes naw. If RISE get into parliament, and lay that resolution before it, what is the SNP going to do when the assertion is they have been elected to Government by a sovereign people? The only thing the SNP could do to retain any credibility is to vote for that resolution and assert the sovereignty of our people."

He branded new powers for Holyrood over income tax "a trap" and said he could not understand why his party had not submitted a minority report to the Smith Commission rather than signing up to the cross-party proposals in full.

Mr Sillars, who referred to RISE as "we" and "us" during his speech, added: "We should be ashamed of the Scotland we have today. One in four children living in poverty... how can we tolerate that? We've got to go out and say to people, 'is this the Scotland we are asked to be proud of?' Isn't this the Scotland we can make better by policies that make working class life the priority in our society?"

He went on to praise Mr Fox as a man of "deep socialist integrity" and said he was doing his best to get the ex-MSP and Ms Boyd elected. Mr Sillars insisted he was not concerned about being kicked out of SNP for campaigning for another party despite his actions being a clear breach of the rules and sparking anger among some party figures.

He added: "I may be regarded by a dissident by the leadership, but I've got a lot of affection for the party, a lot of personal and political friends in the SNP. I don't see any problem for me, at my age at the end of my political life, helping what I regard as an extremely important socialist movement.

"I talk to people inside the party and they think it would be absolutely crazy for any disciplinary action to be taken against me at my time of life. I understand the constitutional position as well as anybody else and I've been given a fair degree of licence over the years which I am grateful for."