In a lengthy piece analysing the challenges facing his party, George Kerevan accused the First Minister of abandoning the grass roots independence movement in favour of the support of the “Quisling” Scottish middle class.
The former MP for East Lothian claimed Ms Sturgeon’s “Presidential style” and “artful” use of daily Covid-19 briefings meant that she now dominated the political discourse in Scotland.
“These manoeuvres have seen Sturgeon’s personal poll ratings reach stellar heights and the emergence of a sustained majority supporting independence, for the first time ever,” he wrote.
But he described the support for independence among middle class voters as “wafer thin”, claiming that the SNP lead in the polls is “based solely on the political charisma of ‘President’ Sturgeon and the SNP leadership’s slavish support for the institutions of the EU.”
"This provides the professional, pro-EU Scottish middle class with the necessary assurance that the First Minister will personally protect their narrow interests both from incompetent, Little Englander Boris but also from the anti-austerity, democratic passions of the pro-indy underclass in the housing schemes,” he wrote.
“To reassure the middle class that the SNP now represents continuity rather than revolution, Sturgeon has had to neuter the mass movement, lest noisy street politics upset the Edinburgh New Town set.
“That she is able to do this is a reflection of the rapid, uncontested bureaucratisation of the SNP itself.
“To keep these newfound bourgeois independistas on board, Sturgeon must eschew anything resembling threats of an unsanctioned second referendum, never mind (God forbid!) declaring a Scottish UDI (unilateral declaration of independence).”
By appealing to the Scotland's middle-class “Quisling institutional base”, Mr Kerevan argued that Ms Sturgeon and the SNP risk leaving the independence campaign in “an endless limbo.”
“No-one is accusing [Ms Sturgeon] of consciously abandoning the independence struggle.
“But by focusing everything on herself, and by forsaking the use of mass pressure to force Boris & Co. to the negotiating table, Sturgeon could very well pluck compromise from the jaws of victory.”
“Even when they accept the SNP leadership is drifting rightwards, many party loyalists argue that now is not the time to “rock the boat” - especially as popular support for independence is running at record levels.
“But Sturgeon’s softly-softly tactics leave the movement impotent if the British state turns nasty – which it will,” he added.
"Worse, the sort of independent Scotland the present SNP leadership is leading us toward will only enshrine the rule of the complacent Scottish middle class and rapacious foreign multinationals, to the detriment of the working people.
"We face a choice between defeat or a new form of servitude."
Mr Kerevan served as the MP for East Lothian after winning the seat from Labour at the 2015 election.
He was a member of the House of Commons Treasury Select Committee, before losing his seat to Scottish Labour candidate Martin Whitfield in the snap election in 2017.
His former East Lothian constituency was retaken for the SNP in 2019 by Kenny MacAskill.
The SNP has been approached for comment.