A leading figure in the coal gas industry has lambasted environmental campaigners for being against fossil fuels, against manufacturing and against employment.

Dr Harry Bradbury, chief executive of Five Quarter, one of the companies that wants to gasify coal under the seabed around Scotland, launched an angry attack on green activists. He also criticised the Scottish government for ignoring the advice of its own experts when it announced a moratorium on onshore gas developments last week.

"The very fact that the green lobby is in favour of expanding the moratorium is a clear indication of their anti-fossil fuel stance, which translates to being anti-manufacturing and anti-employment," Bradbury told the Sunday Herald. "We can all go back to sackcloth and ashes."

He compared environmental demands to extend the temporary ban on fracking and coalbed methane to include underground coal gasification (UCG) to the controversy over Andy Murray's fiancé, Kim Sears, swearing during a tennis match in Australia. If you were upset about that, he suggested, by the same logic you would ban all ball sports.

It was "simple-minded" for environmental groups to argue in favour of renewable energy sources like wind and solar instead, he argued. They could only provide electricity, which accounted for just 18 per cent of the UK's energy needs. "We need gas, and we need renewables," he said.

Bradbury, whose company has three exploratory licences for UCG in the Forth and Solway firths, stressed that it was a completely different process from fracking. Called "deep gas winning", it used sophisticated chemical engineering and pyrolysis to flush out gases like methane, carbon monoxide and hydrogen trapped in rocks.

He expressed concern about the impact of the Scottish government's moratorium on employment at Grangemouth."They are flying in the face of all the expert advice they themselves asked for," he said. "It's a complete nonsense".

Dr Stuart McIntyre, an energy and economics lecturer at Strathclyde Business School, pointed out that the commercial development of UCG depended on making carbon capture and storage work. "Progress in this area has been very slow," he said.

"Until we have carbon capture working at industrial scale, we won't be able to exploit UCG at any kind of significant scale for electricity generation. So while licenses have been granted for UCG exploration, that doesn't mean that extraction activity is actually taking place."

McIntyre contended, though, that new, affordable sources of gas were needed. "If we cannot develop new domestic sources of gas supply, we will become even more dependent upon imports of gas from abroad, raising energy security concerns," he said.

"If we are serious about minimising the environmental impact of fossil fuel extraction, we ought to be taking a truly global perspective. We should compare the environmental impact of domestic extraction to the environmental impact of importing our fossil fuel needs from abroad."

When approached by the Sunday Herald, Cluff Natural Resources initially promised to comment, but then declined to say anything. In November it said there was an estimated 335 million tonnes of coal under the 3,687 hectares of seabed it is exploring off Kincardine.

In January, it announced it had hired planning consultants to progress the project, and would be seeking planning consent. "The project will comply with all relevant planning, permitting and environmental protection legislation," the company said.