The Scottish Government has ditched a major contract to investigate the environmental impact of fracking after the Sunday Herald revealed it had been awarded to an avowed supporter of the controversial technology.

Earlier this month ministers gave a £36,000 contract to the Edinburgh firm Ramboll Environ, but in a dramatic u-turn on Friday night, the deal was abruptly dumped.

Ramboll’s senior consultant on the environmental impacts of fracking and other unconventional gas technologies is Katharine Blythe. On social media sites she has repeatedly made it plain that she is “backing fracking”.

A few hours after the Sunday Herald asked her about her support for the industry on Thursday, her Facebook and Twitter accounts - along with her many comments in favour of fracking - disappeared from public view. She declined to comment.

Then late on Friday the Scottish Government confirmed that it had cancelled the contract with Ramboll. “The impartiality and integrity of this research is crucial,” said a spokeswoman for Deputy First Minister, John Swinney.

“The issues raised regarding this contract may call this into question. As a consequence we have agreed with the contractor, by mutual consent, not to proceed with the contract.”

The contract was one of three awarded by Scottish ministers on February 12 as part of their promise to examine the implications of the unconventional gas industry while maintaining a moratorium on developments. The contracts were disclosed by the Sunday Herald last weekend.

Blythe is known to environmental and community groups because she appeared as a consultant at a public inquiry in March and April 2014 in support of Dart Energy’s bid to exploit coalbed methane at Airth near Falkirk. In July 2014 she joined Ramboll Environ as an “unconventional oil and gas sector environmental expert”.

In an article in June last year she argued that uncertainty was “problematic for an industry in its infancy”. She described how the Grangemouth petrochemical giant, INEOS, had applied for fracking licences “with support from Ramboll Environ UK”.

In recent years Blythe has frequently engaged on social media with opponents of fracking in defence of the industry. On her personal Facebook page she liked the pro-industry group, ‘I’m backing fracking’, and joined a group called ‘Fed up of anti fracking disruption and nonsense.’

On a pro-fracking Facebook page she agreed that she was the author of a Twitter account @DrLantern called ‘MiserableBallOfHate’. Its profile picture was a black cat with the slogan “I’m backing fracking”.

On July 31 2015 the account invited people to sign a pro-fracking petition, and on August 18 it tweeted congratulations to INEOS for winning shale gas exploration licences. Last Sunday it hinted at involvement in the Scottish Government fracking research contracts.

But Blythe’s Facebook and Twitter accounts were both deleted from public view after she was asked to comment. She referred media inquiries to the Scottish Government, which within 24 hours dropped Ramboll as contractor.

The Lothian Labour MSP Neil Findlay questioned whether ministers were guilty of cock-up or a conspiracy. “It looks awfully like the Scottish Government have been caught red handed and withdrawn this contract only after they knew they had been caught,” he said.

“This is yet more evidence that their moratorium is a complete sham. It would have taken literally seconds to discover Ms Blythe is a staunch supporter of fracking, so appointing her in the first place really calls into question processes of due diligence when awarding public contracts.”

The Glasgow Green MSP Patrick Harvie argued that the u-turn showed how Scottish ministers had to be watched. “Without pressure from voters and the media, this dodgy research contract would have gone ahead unnoticed,” he said.

“The Scottish people deserve clarity ahead of May's election, yet all they are getting is an inquiry that's increasingly hard to trust. Public opposition to fracking is crystal clear, but the SNP's position remains ambiguous and confused.”

The Broad Alliance of community groups across Scotland opposing unconventional gas developments welcomed the government’s sudden change of heart. “We trust that other, and future, contracts will be carefully scrutinised to ensure that contractors are independent and unbiased,” said the group’s spokesman, Donald Campbell.

Professor Andrew Watterson, who heads the Occupational and Environmental Health Research Group at the University of Stirling, agreed it was wise to axe the contract. “However, the awarding of contracts for the moratorium still raises wider questions about how potential conflicts of interests and partisan positions are and can be identified in all contractors and their staff,” he said.

Friends of the Earth Scotland urged ministers to review the tenders for other research projects to check that no individuals with an obvious bias were involved. “The debate around fracking is so highly charged that clear conflicts of interest could completely derail the moratorium research processes, sowing corrosive mistrust at the outset,” warned the environmental group’s head of campaigns, Mary Church.

Ramboll Environ stressed that the contract was ended by mutual agreement. “We are of course disappointed not to be able to bring our global expertise in this issue to this key research,” said the company’s UK Managing Principal Matt Davies.

“Integrity and impartiality are central to all that we do at Ramboll Environ. I am satisfied that the circumstances here are an isolated incident. As one of the UK’s leading environmental consulting firms, we will continue to work with our clients and other stakeholders to bring scientific rigour, objectivity and independence to this important debate.”

The Scottish Government stressed that research as part of the moratorium would carry on. “We have publicly committed to carry out one of the world’s most comprehensive and impartial research programmes into fracking and an extensive public consultation which will allow interested parties to express their views,” said the government spokeswoman. “This will continue.”

Two other contracts were awarded this month by ministers following a competitive tender process. One was to the British Geological Survey to investigate seismic risks, and the other to the consultancy AECOM to research decommissioning.

The accountancy firm KPMG is also studying the economic impact, while the Committee on Climate Change, an independent body that advises government, is looking at the potential climate impacts. The government’s Health Protection Scotland is undertaking a public health impact assessment.