The Scottish Government could be forced to rely on shale gas that has been fracked in England to keep homes north of the border warm, the First Minister has been warned.

Conservative leader Ruth Davidson demanded Nicola Sturgeon "gives the country some proper answers" on whether the controversial process will be given the green light in Scotland.

She challenged Ms Sturgeon on the issue two days after the first giant tanker filled with shale gas from the United States arrived at the Ineos chemical plant in Grangemouth.

That facility would have been closed without the imported gas, the company has said, with the loss of 10,000 jobs.

The Scottish Government has put in place a moratorium on fracking and is currently awaiting the results of research, before then carrying out a public consultation.

Ministers will then make a decision on whether to allow unconventional gas extraction.

But Ms Davidson said: "Nobody is well served by a government that hides from view and kicks this into the long grass."

She added: "This is a First Minister that doesn't want to admit that her Government's failure on energy will leave us reliant on others to keep our homes heated.

"There are 10,000 jobs in central Scotland that are reliant on shale gas coming here from other countries, but we still have no answers on shale gas at home."

She accused the SNP of "total double standards on this matter", saying: "When it comes to shale gas in this country, they have leapt on their high horse, preached about a moratorium and boasted that they're the planet's best friend.

"But when the gas is poured into a tanker and shipped all the way across the Atlantic to our shores, then they turn a blind eye and hope that if they ignore it everybody else will too.

"It's quite possible that shale gas in the rest of the UK will get the go ahead soon, if local communities back it. If it does, providers say that much of that gas will go to Grangemouth and will end up in the national grid, powering many Scottish homes.

"So we could end up with a ban on Scottish gas but with Scottish homes reliant on English gas to keep the pipes warm."

Ms Sturgeon, however, told her the Scottish Government is "taking a cautious, evidence-based approach to the issue of shale gas and fracking", insisting that is the "right approach" given concerns about possible impacts on the environment and local communities.

The two leaders clashed on the issue during First Minister's Questions at Holyrood, with Ms Sturgeon telling the Tory it is a "bit rich" for her to challenge the SNP on energy given the UK Government's support for new nuclear power.

She insisted her Government would not "play fast and loose with our environment", and added: "Obviously the decision about the import of shale gas to Grangemouth is a decision taken by Ineos, which is a company that is absolutely free to take those decisions.

"In terms of the issue of fracking in Scotland, I appreciate that the position of the Scottish Conservatives is to ride roughshod over local opinion, over environmental concerns, over the range of other concerns that have been raised.

"That is a position Ruth Davidson is perfectly entitled to argue. I think it's better to take the evidence-based, precautionary approach that this Government is taking because we shouldn't play fast and loose with our environment. So we will continue to undertake the work we have set out."

She stressed the issue will be "carefully considered by the Scottish Government".

And Ms Sturgeon added: "I know the Scottish Conservatives are a party controlled by London, but in the era of devolution I think it is right we take the decisions about fracking in Scotland here in Scotland and in our national Parliament, and that's what we will continue to do.

"So given the concerns that have been raised both domestically here in Scotland, in other parts of the UK and in many other countries, we will continue to take that evidence-based approach and I will leave Ruth Davidson to explain to communities across the central belt of Scotland why her party would choose to ride roughshod over the concerns that have been raised."