SCOTLAND’S professional Unionists have been accused of a “very low” attack on a professional pollster after he signed up to help find members for the new Citizens’ Assembly.

Former Ipsos Mori boss Mark Diffley – who worked for Better Together – beat off competition from other firms to win a £22,000 contract to find 120 members of the public to take part in the convocations tasked with discussing the kind of country Scots are “seeking to build”.

But the Tories, Scotland in Union and Unionist blogger Kevin Hague were irked because of Diffley’s role as research and polling adviser to Progress Scotland, the pro-independence organisation set up by former SNP chief Angus Robertson.

Scotland in Union suggested it was “highly questionable”.

But Andrew Wilson, the author of the SNP’s Growth Commission, hit back on Diffley’s behalf.

He tweeted: “I have no idea how Mark votes. I do know he did a great job for the Better Together campaign which is why it’s great to have him contracted to advise @progressscot. This attack on the integrity of a high quality professional researcher trying to build a business is low. Very low.”

Diffley’s consultancy and research firm was established two years ago after he left Ipsos Mori where he had worked as the lead pollster for the UK Government in the run-up to the 2014 independence referendum.

Scottish Tory chief whip Maurice Golden said: “Mark Diffley is a respected pollster, and has been for some time in Scotland.

“But given his new role with the nationalist movement, this appointment will only serve to increase suspicion about the Citizens’ Assembly. The SNP is doing very little to persuade people this will be anything other than an independence talking shop.”

Pamela Nash, CEO of Scotland in Union, said: “It is highly questionable that the SNP Scottish Government has appointed Mark Diffley to this role when he is currently a public figurehead of an anti-UK think tank.

“There is absolutely no doubt that Mark is an experienced independent pollster and very much respected for his professionalism in Scotland.

“However, for the Citizens’ Assembly to have the trust of the public, there can be no hint of a conflict of interest. It is already widely seen as yet another SNP vehicle for breaking up the UK, and this appointment by the Scottish Government will just add to public distrust of this project.”

Hague said: “How arrogant and complacent must the SNP be to ignore such a blatant conflict of interest?

“It’s as if they’ve given up pretending that these Citizens’ Assemblies would be anything other than an indyref2 campaigning tool”.

Diffley reacted angrily to Hague’s questioning of his professionalism and integrity: “Actually, if you bothered to check you’d know I have worked across the political divide my whole career, including for the UK Govt. during the indyref (who existed expressly to make a case for the union!) and have worked with parties of all colours in Scotland for nearly 20 yrs.

“The notion that I (or others) can’t use their expertise to offer impartial advice without fear or favour is just nonsense.”

The Scottish Government said Diffley had met “all the contract conditions” including criteria to prevent “potential conflict of interest”.