British Energy underwent financial restructuring in October

Two reactors at Heysham 1 in Lancashire are now expected back online at the end of this month, later than the mid-November target announced previously.

The financial impact could now be much more than the �20m-30m that the firm had predicted.

Earlier this year the company reached a life-saving debt restructuring deal.

It is now expected that both (Heysham 1)reactors will return to service towards the end of November British Energy spokesman

At Heysham 1, both reactors were shut down on 28 October following the failure of a sea water cooling pipe.

At Sizewell B in Suffolk a suspected "anomaly" was found at the plant when it was shot down in October for routine maintenance.

More tests revealed there was no anomaly, but it meant the plant was closed for two weeks longer than the normal shutdown for maintenance.

It is now set to return to service imminently.

British Energy said the combined loss of output was now likely to be in the region of 1.1 to 1.4 terawatt hours of power, and not the 0.8 terawatt hours previously estimated.

East Lothian-based British Energy said: "The delayed return of Sizewell B and Heysham 1 will have a further adverse impact on the group's cash position."

'Pressure on resources'

In June the group announced losses of �4.3bn after slashing the value of its power plants.

At the start of October key creditors agreed to write-off what they were owed in exchange for 97.5% of the newly-restructured firm's shares, and about �425m in new bonds.

On Thursday the company said the continued reactor closures and other factors "continue to put pressure on our liquid resources".

It said it was addressing its problems, and looking to return the Lancashire reactors to service as soon as possible.

Decommissioning help

The company continued: "Based on the inspection programme, which is still continuing, and the scope of the work identified to date, it is now expected that both reactors will return to service towards the end of November."

It added that it had 2 terrawatt hours left of the 5 terrawatt hours of power set aside for unplanned outages in the year to 31 March.

British Energy's biggest plant is at Hartlepool, with others at Hinkley Point, Somerset; Hunterston, Ayrshire; Dungeness, Kent; and Torness, East Lothian.

As part of its rescue package, the government will help meet some of the firm's future liabilities, such as the cost of decommissioning nuclear power plants.