Scottish Government will not take final decision on fracking in Scotland until 2017

The Scottish Government revealed the timetable for reaching a decision on fracking as Mr Ewing bowed to growing pressure from within the SNP and extended the existing moratorium on the technique to include underground coal gasification, or UCG.

A large protest at plans to use UCG to exploit resources beneath the Firth of Forth is planned for Sunday.

Mr Ewing said an in-depth  research project to determine benefits and possible risks of unconventional gas extraction would begin soon.

A report will be published in the Autumn of next year, after May’s Holyrood election.

A subsequent public consultation will not conclude until the Spring of 2017.

Mr Ewing said: “The studies announced today constitute an extremely thorough and wide-ranging examination of the potential impacts of unconventional oil and gas and underlines the Scottish Government policy of taking a precautionary, robust and evidence-based approach to this technology in stark contrast to the gung-ho approach of the UK Government.

“Ministers have held meetings with representatives of environmental non-governmental organisations, community groups, industry bodies and local government.

“Those meetings have helped us to prepare for the research and public consultation processes. As a result, we have planned a robust and thorough research process and a wide-ranging and participative consultation process.”

He added: “The public will understandably wish to study the outcome of the research process and thus the public consultation will not begin until the findings of the research process have been published.”

Patrick Harvie MSP, leader of the Scottish Greens, said:

"Today's announcement shows that consistent pressure on ministers from Greens, campaigners, communities and even members of the SNP is working. Ministers previously said underground coal gasification was out of their hands but they've done the right thing by bringing it into the moratorium.

"Uncertainty remains for thousands of communities across Scotland who still don't know what the Scottish Government's long-term policy is. It's a worry that the energy minister is still asking people to see what he calls 'potential opportunities', when it is clear that further extraction of fossil fuels is incompatible with Scotland's climate change responsibilities and poses huge risks to our communities and our economy.

"As we head towards the 2016 election it is clearer than ever that the best way to say no to fracking and other risky fossil fuel developments is to elect more Scottish Green MSPs."

The SNP had been accused of attempting to suppress debate within its own ranks after party HQ watered down a conference resolution calling for a moratorium on fracking to be extended.

A potentially divisive debate is to take place at the party's conference on unconventional oil and gas, based on a resolution that was submitted ahead of the event by the SNP's Leith branch calling for a u-turn in Scottish Government policy.

It has emerged that party bosses have rewritten the submission without consultation with the branch, leaving delegates with the chance to agree to a far weaker position than was proposed by grassroots members.

A paragraph inviting the conference to agree that it was concerned at research from America showing "dramatic environmental and health impacts" associated with unconventional gas extraction has been cut entirely.

Branch members also found that their submission "inviting the Scottish Government to extend the current moratorium on fracking to include the technologies involved in underground coal gasification and unconventional gas extraction" had been weakened. The final agenda for the debate a week tomorrow invites the conference to call on the Government to only "consider" extending the moratorium, a move energy minister Fergus Ewing has already rejected.

One member of the branch said that there was anger that SNP bosses had “taken the teeth” out of a motion they already considered to be moderate. It is understood that an appeal was made to party HQ to revert to the original wording, but it was rejected.

Dr Richard Dixon, director of Friends of the Earth Scotland, criticised the party leadership for allowing only a tame motion to be debated. Far stronger submissions calling for an outright ban on unconventional oil and gas extraction were rejected by a powerful SNP committee that agrees what can be put to members at conference, while it is understood that proposed amendments to the watered down Leith resolution were also ignored.

He said: "By ignoring calls for a full ban the party has clearly tried to prevent the conference from passing anything that pushes them into a strong policy on fracking and unconventional fossil fuels. But ignoring the strong feelings among the grassroots members by allowing only a weak motion onto the agenda sets them up for a bad tempered and embarrassing debate next week."

The move comes as a split in the party over unconventional gas extraction threatens to boil over at the Aberdeen conference. Many party members and a significant number of SNP parliamentarians are strongly opposed to unconventional gas extraction, with an internal group, SNP Members Against Unconventional Oil and Gas, recently being established.

But despite imposing a moratorium on fracking, the party leadership have so far refused calls to extend the temporary ban to underground coal gasification, a process that sees coal seams set alight underground and gas siphoned off to the surface. A large protest against plans to exploit the technique under the Firth of Forth is to take place on Sunday.

Meanwhile, SNP ministers are lobbying for tax revenues from fracking to be assigned to Holyrood and have offered private assurances to energy firms that they are open to the technique, fuelling speculation that it will eventually be given the green light after next May's elections. Ineos, the owner of the Grangemouth industrial complex which wants to establish a fracking industry in central Scotland, has bought a stall at the SNP conference in the hope of winning over members and nationalist politicians.

Sarah Boyack, Labour's environmental justice spokeswoman, said the SNP was in "disarray" over unconventional energy just days before its conference. She added: "The SNP Government is hiding behind a moratorium, delaying vital public consultation, and astonishingly their HQ is watering down its members’ motions.

"In July Fergus Ewing refused to include underground coal gasification in his moratorium and I doubt he’s got any plans to agree with members in Leith. Last month the First Minster told me that she’d take a 'precautionary, careful, cautious and evidence-based approach' to fracking so the fact that SNP HQ has deleted reference to their own members concerns regarding scientific evidence raises eyebrows."

Adam McVey, an Edinburgh SNP councillor and treasurer of the Leith branch, insisted members were happy with the changes. He added: "It gives us the chance to debate an important subject that branch members were passionate about, and we hope conference will pass our motion."

SNP spokesman said: “Debating points are for the conference hall not the text of a resolution. Motions must be concise and follow the guidance issued by the agenda committee.”