Flows of Norwegian gas through the new Langeled pipeline to Britain could exceed 40 million cubic metres one day this week, an industry source said on Monday.

Langeled began commercial flows of gas into Britain on Sunday but some more gas is still being pumped into the system for continuing tests at the Easington terminal in northeast England.

There are going to be a few days of further commissioning gas coming through, the source said. On one day you will probably see 40 mcm or a bit more coming through... Then it will revert to normal commercial gas... You will probably see quite big volumes of gas coming through over the next few days.

He could not say which day of the week flows of gas would top 40 mcm.

The new supply line, which is big enough to flow up to 70 mcm a day, is set to meet up to a fifth of the country's gas need, Norway's pipeline operator Gassco said on Sunday.

Although Sunday was the official start up date for the southern leg of the 1,200 km Langeled pipeline, Norwegian industrial group Norsk Hydro said it began selling gas through the pipeline already on Wednesday last week.

Langeled is one of several new gas import projects being built to offset a rapid decline in production from the UK's ageing North Sea fields.

The gas enters the Langeled pipeline at the Sleipner riser platform in the Norwegian sector of the North Sea and lands at Centrica's terminal in England.

Gas from Ormen Lange will begin flowing through the pipeline from October 1, 2007, once the northern leg of Langeled is completed.