Culzean will account for around 5pc of Britain's gas consumption, bringing to 18pc the proportion of the country's gas demand supplied by Total.

Total has a 49.99pc stake in Culzean, while BP has 32pc and JX Nippon has 18pc.

"The Culzean project is delivered ahead of schedule and more than 10pc below the initial budget, which represents capex savings of more than $500 million.

This has been achieved thanks to the excellent performance of the project teams in charge of the construction and drilling operations," said Arnaud Breuillac, President of Exploration & Production at Total.

Total's shares were up 0.5pc in early session trading.

"For the French major, production from Culzean will play a big part in it being the biggest UK gas producer for the foreseeable future," said Wood Mackenzie research associate Glenn Morrall.

"The UK continues to deliver for Total, with the Culzean news following on from recent exploration success as an operator at Glendronach and partner at Glengorm," he added.