TRADE unionists within the SNP are pushing for a total ban on fracking across Scotland, as the party leadership comes under growing pressure from members to adopt a tougher stance against unconventional energy extraction techniques.

The party's Trade Union group, which boasts more than 15,000 members, has submitted a resolution to the SNP conference in October calling for a moratorium announced last January to become a blanket ban citing environmental concerns including earthquake risks and potential impacts on public health.

The decision over whether the resolution will be debated at the conference will be decided by the SNP's standing orders and agenda committee. If it is selected and backed at conference, it will become party policy.

Kirsteen Fraser, secretary of the SNP’s Trade Union group, said the resolution came at the behest of members. She added: "I think we’ll see the membership pushing the policy forward. There are a lot more members now and that will mean change within the SNP on many issues. I know there have been many moves to get a more concrete position when it comes to fracking."

The moves from left-wing factions within the SNP comes after the party leadership was accused by opponents of misleading the public over its position on fracking.

Despite presenting itself as anti-fracking during the general election campaign, SNP energy minister Fergus Ewing has so far refused to say whether test drilling is covered by the moratorium, while Finance Secretary John Swinney has called for potentially lucrative tax revenues to be assigned to Holyrood.

Ineos boss Jim Ratcliffe, who plans to begin test drilling within 18 months, met Nicola Sturgeon on the day the moratorium was announced and has said he has been assured by the SNP Government that it is "not against" fracking.

Meanwhile, the Scottish Government is facing growing calls to extend the moratorium to underground coal gasification (UCG), a process which sees coal set alight underground and gas extracted. Ministers have the powers to block developments but have so far refused to do so, despite Cluff Natural Resources, which wants to exploit coal under the Firth of Forth, saying it will submit a planning application within months.

SNP MP John McNally, the convenor of the party group on fracking at Westminster, said the moratorium should be extended to UCG while nationalist MSP Angus MacDonald has called on Mr Ewing to spell out what is covered by the moratorium.

Labour's energy spokesman Lewis Macdonald backed the calls, saying: "The SNP’s position on fracking is now so unclear that even their own MPs and MSPs are asking for clarity."

Edinburgh MP Tommy Sheppard, one of the SNP's most high-profile Westminster members, told online investigative journalism platform The Ferret that UCG was "more problematic than fracking because it has a greater risk of underground explosions" and that he believed any planning application would be refused.

It also published a letter from Algy Cluff, the energy tycoon behind Cluff Natural Resources, to Alex Neil, the minister with responsibility for planning.

He asked for written confirmation that UCG was not included in the moratorium so it could be shown to shareholders, and warned blocking his plan would mean losing £250 million of investment in Scotland. Mr Neil complied with the request within days.

Responding to the correspondence, WWF Scotland director Lang Banks said: "No company should ever be allowed to hold Scottish Ministers or Scotland's environment to ransom like this."

Scottish Conservative energy spokesman Murdo Fraser described the SNP position on fracking as "very hypocritical", adding: "Privately it accepts the reality that shale is too good a source of economic potential and energy to ignore. But at the same time, it is terrified of alienating its swathes of left-wing members."

A spokesman for the SNP said a planned consultation would allow stakeholders and communities to have their say. He added that the Scottish Government stance was backed by delegates at the SNP conference in March.