Media playback is unsupported on your device Media caption The BBC's David Shukman explains how fracking works

French oil and gas company Total will invest at least $21m (£12.7m) in the UK's shale gas industry.

UK energy firm IGas Energy said it had agreed a deal to hand Total a 40% interest in two shale gas exploration licences in Lincolnshire.

The investment makes Total the first of the so-called "oil majors" to invest in shale gas in the UK.

Total will pay $1.6m in back costs and fund a work programme of up to $46.5m, with a $19.5m minimum commitment.

"The entry of the first major into UK shale gas licences is a further endorsement of the potential that exits... and demonstrates strong support for our operating capability," said IGas Energy chief executive Andrew Austin.

Pressure

Total's senior vice president for Northern Europe Patrice de Vivies said the deal marked an "important milestone" in a "promising onshore play".

The British Geological Survey estimates there may be 1,300 trillion cubic feet of shale gas present in the north of England.

But the process to extract shale gas - called "fracking" - has proved controversial.

Fracking - short for "hydraulic fracturing" - involves drilling deep underground and releasing a high-pressure mix of water, sand and chemicals to crack rocks and release gas stored inside.

Analysis That Total is now getting involved in the UK shale gas industry is not insignificant. The oil majors (BP, Shell, Total, Exxon, and Chevron) waited in the wings for five years in the US while smaller exploration companies drilled for shale gas. When it became clear there were major commercial flows in America, then the majors piled in. Now it looks like the majors are getting interested in Britain at a very early stage - thanks in no small part to the confident reserve estimates from the British Geological Survey and the open arms of the UK government. The large energy players bring deep pockets and serious expertise with them and will be able to extract, sell and distribute any found gas quicker than smaller companies. The advantage for the consumer could also be mouth watering - US energy costs are now a third of those in Europe. If Britain can extract 10% of the estimated reserves it could supply the entire country for almost 50 years.

Total's move comes as the government is expected to introduce more incentives to encourage local authorities to allow drilling for shale gas, according to environmental campaigners Greenpeace.

Under the measures, local authorities would keep all income from business rates paid by companies drilling for shale gas, instead of giving it to the UK treasury.

In December, a report commissioned by the Department of Energy and Climate Change (DECC), said more than half of the UK could be suitable for fracking.

Protests

The process has attracted anti-fracking protests in the UK, with environmentalists fearing the technique could cause small earth tremors, water contamination and environmental damage.

But the BBC's Joe Lynam said the announcement will be welcomed by the government which has championed shale gas as a major source of the UK's future energy needs.

Our correspondent said Total's entry into the UK's shale gas market is not insignificant and the other four major oil and gas companies could follow.

If Britain can extract 10% of its estimated gas reserves, it could supply the entire country for 50 years, our correspondent said.

Boost

In August, Prime Minister David Cameron said the whole country should support fracking, insisting it is safe if properly regulated and could create thousands of jobs and reduce energy bills.

Shale gas has helped boost the domestic energy industry in the US in recent years, where oil production has risen and gas prices have plummeted.

Major oil companies waited for more than five years before investing in shale gas production in the US, but the UK will receive this major oil and gas company backing while the industry is still in its infancy.

Image copyright (C) British Broadcasting Corporation

Senior government sources told the BBC that the Total investment was a strong vote of confidence in the sector.

That view was echoed by business lobby group, the Institute of Directors, which said shale gas could be a "New North Sea" for Britain.

'Bribery'

However, Greenpeace climate campaigner Lawrence Carter, said: "Total, a French company who can't frack in their own country because the French government has stopped the French countryside being ripped up have now turned their sights on the UK countryside where the UK government seem happy to allow the industrialisation of our green and pleasant land.

He said the UK government "are pushing ahead with selling off two-thirds of Britain for drilling without a public mandate".

Mr Carter said the government was "resorting to straight-up bribery" by allowing local authorities to keep all of the business rate income from companies drilling for shale gas.

The UK currently consumes only three trillion cubic feet of gas annually.

The government previously unveiled a package of reforms to encourage development in the industry.

They included new planning guidelines to make the process of approving new drilling sites more streamlined, and a consultation on tax incentives to encourage exploration.

Communities affected by shale gas drilling are also expected to receive £100,000 in "community benefits" and 1% of production revenues, should sites start producing gas.

Total has 97,000 employees operating in more than 130 countries.

According to its website, it is the world's fifth largest publicly traded oil company.