Scotland has modest shale gas and oil resources, an assessment by the British Geological Survey suggests.

The estimates for the Midland Valley suggest shale gas resources of 80 trillion cubic feet - considerably lower than the 1,300 trillion cubic feet thought to be in the Bowland shale in northern England.

There is an estimated 6 billion barrels of shale oil in the area, which stretches across Scotland and includes Glasgow and Edinburgh, slightly more than the central estimate of 4.4 billion barrels in the Weald Basin in southern England.

But the amount of gas and oil that can be extracted from the shale is likely to be far lower than the total resource. In the US shale oil exploration has only been able to access up to 10% of the total oil.

The Midland Valley's estimates are particularly uncertain, experts said, because the area has fewer historic wells and less seismic data to rely on than other areas which have been assessed.

More exploratory drilling and testing is needed to determine how much of the oil and gas resource can be recovered.

Business and Energy Minister Michael Fallon said: "Making the most of Britain's home grown energy is crucial to keep job and business opportunities, widen tax revenues and reduce our reliance on foreign imports.

"We know that shale gas alone won't be able to supply all of our energy needs, but the environmentally responsible exploration of shale gas could contribute to our energy mix.

"Only the broad shoulders of the United Kingdom can attract investment in new energy sources and maintain the UK's position as one of the world's great energy hubs - generating energy and generating jobs.

"The UK's energy security is among the best in the world, backed by a large consumer and tax base that can afford to support our world-leading energy industries and make us such an attractive place to invest."

Professor Mike Stephenson, director of science and technology at the British Geological Survey, said: "The central estimate of shale gas in place is 80 trillion cubic feet and the central estimate for shale oil in place is 6 billion barrels of oil but reserves cannot be calculated at this stage before drilling and testing take place.

"The Midland Valley of Scotland has complex geology and a relative lack of data compared to the previous DECC-BGS Bowland-Hodder and Weald Basin studies."

Environmentalists said the assessment showed there was not going to be a shale gas or oil "bonanza" in Scotland, and called for ministers to commit to leaving fossil fuels in the ground.

WWF Scotland director Lang Banks said: "It's clear that there's not going to be a shale gas or oil bonanza in Scotland any time soon.

"While this study should change nothing about Scotland's aim to decarbonise its power sector and go fully renewable, in the wider interests of tackling climate change it's time for Scottish ministers to commit to start leaving some fossil fuels, including shale gas, in the ground.

"We already know our planet's climate can't afford the risk of burning the fossil fuels we already know about. So, to plan to find and burn even more should really be a non-starter.

"Only last week it was revealed that Scotland is now generating record amounts of renewable electricity, while other studies have shown we could generate all of our electricity needs without the need for new fossil fuel burning.

"Whether it is shale gas, coal or oil, Scotland really needs to begin transitioning away from polluting fossil fuels."

Labour's shadow energy minister Tom Greatrex insisted that extraction of shale gas "should only happen in a context of robust regulation, comprehensive monitoring and local consent".

The MP for Rutherglen and Hamilton West said: "In March 2012, I set out Labour's six regulatory conditions that would need to be met before shale extraction can be permitted in line with a commitment to decarbonise our electricity supply by 2030.

"Today's announcement is about the amount of resource - but as the British Geological Survey rightly emphasises, what is actually extractable cannot be estimated without a detailed understanding of flow rates. Shale should not be presented as a silver bullet - rather a potential contributor to where we source the gas eight in 10 of us use for heating.

"There are many concerns that the Scottish environmental regulator, SEPA, has neither the capacity nor the expertise to monitor any future shale extraction effectively. SNP ministers need to ensure they are able to do so to ensure public confidence in the monitoring of regulatory activity."