Fracking company Cuadrilla has said it has seen the first gas recovered from its Preston New Road operation.
It said the natural gas returned to surface, along with water being recycled from the shale rock, after hydraulic fracturing a small section of the shale surrounding the first of two horizontal exploration wells.
Cuadrilla, described the news as significant and indicative of the potential of the shale.
It comes the week after it faced calls to stop the fracking operation after a series of micro-seismic events were triggered by the injection of water, sand and chemicals at high pressure into deep lying shale rock.
Francis Egan, Chief Executive Officer of Cuadrilla, said: “The volumes of gas returning to surface at this stage are small.
"However, considering that we are only at the very start of fracturing operations and, given operating constrains, have not yet been able to inject as much sand into the shale as we had planned, this is a good early indication of the gas potential that we have long talked about.”
The company, based in Bamber Bridge, Lancashire, plans to fully test flow rates from the first two exploration wells towards the end of 2018 and into the New Year following the completion of hydraulic fracturing operations which began in mid-October.
Mr Egan said: “This Preston New Road site is being monitored to an unprecedented level. This initial gas flow is by no means the end of the story.
"However it provides early encouragement that the Bowland Shale can provide a significant source of natural gas to heat Lancashire and UK homes and offices and reduce our ever growing reliance on expensive foreign imports.
"This week, three huge tankers carrying liquefied natural gas from across the world, including shale gas imported from the US, will dock in the UK to safeguard our winter gas supplies. If we are able to fully test these wells, without compromising on safety, we have the potential to make a major difference to UK energy supply, security and economic prosperity.”
But Frack Free Lancashire which has been campaigning against fracking pointed to the recent problems with more than 30 earth tremors being caused by the weeks old fracking operation.
A spokesman said: "After the public relations disaster that Cuadrilla have suffered over the last three weeks, and the 25 per cent crash in their parent company's share price over the last 48 hours, Cuadrilla are clearly desperate to be able to give their investors some good news.
“However, it sounds as though they are now claiming that a small quantity of gas that returned when they had to depressure the well (after triggering both amber and red events) is somehow exciting news.
“We doubt that either their investors or the government are going to impressed by this last-ditch attempt to salvage something positive from a three-week series of unfortunate events.
“We look forward to seeing the associated data on the flow rate, which they will no doubt be publishing shortly."
But Babs Murphy, chief executive of the North and Western Lancashire Chamber of Commerce said: “This is great news and early indications are looking extremely promising. Shale gas represents a huge economic opportunity for Lancashire firms not only in terms of winning new business but also creating new jobs and generating new market opportunities.
"It’s now up to all of us to work together to keep as much of these economic opportunities here in Lancashire. Cuadrilla has pledged to seek to buy local. It’s up to us now to raise our game, work together, and take full advantage of this."