The letter from Chancellor George Osborne, written last year, called on Cabinet colleagues to “make it a personal priority” to implement measures to help boost the shale industry.
He called for rapid progress on developing three or four “exemplar drilling sites” to prove the concept of safe shale gas exploration, contingency plans if Lancashire County Council turns down planning applications and a strategy to push fracking to the public.
The letter emerged as the cross-party Environmental Audit Committee (EAC) warned extensive production of unconventional shale gas, which is extracted through fracking, is not compatible with the UK’s goals to cut greenhouse gas emissions.
The committee also called for fracking to be “prohibited outright” in protected areas such as national parks, areas of outstanding natural beauty and ancient woodlands, and banned in all water source protection zones, which feed drinking water aquifers.
In a report published ahead of the final Commons debate on fracking legislation in the Infrastructure Bill, the EAC warned of an “extensive range of uncertainties” over hazards ranging from polluting groundwater and water supplies to noise and disruption.
There was also a lack of public acceptance of fracking, they said.
A number of the MPs on the committee have tabled an amendment to the Infrastructure Bill calling for a moratorium on fracking for shale gas to reduce the risk the UK misses its targets to cut carbon emissions.
A decision is also due this week in Lancashire, one of the areas where shale is thought to be most abundant, on planning applications from shale company Cuadrilla for two new fracking exploration sites between Blackpool and Preston.
But Cuadrilla requested last week that the decision be deferred as it submitted “additional information”, after planning officers for Lancashire County Council recommended the applications be turned down on noise pollution and traffic grounds.
The letter from the Chancellor revealed that he wanted colleagues to “respond to the asks from Cuadrilla” to reduce risks and delays to drilling the first well, and to fast-track planning appeals if the applications for shale exploration in Lancashire are refused.
Friends of the Earth Energy Campaigner Tony Bosworth, who obtained the leaked letter, said: “This letter shows Government and industry working hand-in-glove to try anything to make fracking happen.
“Councillors in Lancashire will be shocked that the Government is plotting with Cuadrilla how to make sure that they can frack in Lancashire even if their applications are rejected this week.”
And he urged: “Rather than push ahead with foisting fracking on local communities, the Government should follow countries and states around the world and call a halt.
“Fracking isn’t the answer to our energy problems - it won’t help us tackle climate change and it brings big risks for health and the local environment.”
The Government has said it is going “all out” for developing a shale industry in the UK - claiming it would create jobs and growth, reduce energy prices and cut the country’s reliance on gas imports.
Supporters of exploiting the unconventional gas also claim it could be a “transition” fuel helping move the UK from the most polluting fossil fuel, coal, towards a cleaner energy supply.
But the Environmental Audit Committee said shale gas could not be considered a transition fuel as any large scale extraction would be at least 10 to 15 years away, by which time dirtier coal would have been phased out.
The shale industry would not be commercially viable unless developed at scale, so it could compete with renewables, but large-scale fracking for the fossil fuel cannot fit within increasingly smaller budgets for how much carbon the UK can emit, they said.
“A moratorium on the extraction of unconventional gas through fracking is needed to avoid both the inconsistency with our climate change obligations and to allow the uncertainty surrounding environmental risks to be fully resolved,” they urged.
The report is published ahead of MPs debating and voting on the Infrastructure Bill, which includes measures to make it easier for energy companies to drill under people’s homes without their permission and allows them to leave “any substance” underground.
The committee criticised the changes to trespass laws to allow fracking without residents’ permission as having serious implications for citizens’ rights, with chairman Labour MP Joan Walley calling on Parliament to throw out the “profoundly undemocratic” proposals.
A spokesman for the Department of Energy and Climate Change said: “We disagree with the conclusion of this report. We have one of the most robust regulatory regimes for shale gas.
“UK shale development is compatible with our goal to cut greenhouse gas emissions and does not detract from our support for renewables; in fact it could support development of intermittent renewables.”