French energy giant Total's Elgin rig, 150 miles (240 kms) from Aberdeen in eastern Scotland, in the North Sea. Total said Monday it had successfully plugged a gas leak at the platform that cost the firm hundreds of millions of dollars and threatened to trigger a major explosion.

French energy giant Total said Monday it had successfully plugged a gas leak at a North Sea platform that cost the firm hundreds of millions of dollars and threatened to trigger a major explosion.

The Elgin platform, 240 kilometres (150 miles) off Aberdeen on Scotland's east coast, was evacuated in March after gas began leaking from the and formed a huge inflammable cloud around the well head.

The company pumped heavy mud into the stricken G4 well for 12 hours on May 15 in a bid to plug the leak.

"Following five days of close monitoring, Total is now able to confirm the success of the intervention," the company said in a statement from its Paris headquarters.

"Several inspection visits to the wellhead platform have confirmed that the leak has completely stopped."

The firm added that engineers would now begin a weeks-long process to set cement plugs in the well, which will lead to it being permanently abandoned.

Earlier this month, the firm estimated that the leak would cost it between $300 and $400 million in lost production and repair costs.

"While we will obviously take on board any lessons to be learned, I want to congratulate all the teams," said Yves-Louis Darricarrere, Total's head of exploration and production.

"Safely evacuating everyone from the platform and adjacent , preventing any serious and recovering control of the G4 well is a highly commendable effort from the teams involved."

(c) 2012 AFP