ScottishPower announced profits of more than �1bn

The Glasgow-based firm also unveiled profits of more than �1bn for the first time in its history.

But a group of Native American Indians, who say the firm's four hydro electric dams have prevented salmon coming up river, are angry at the plan.

They had been in delicate negotiations with Scottish Power over the issue when the sell off news came through.

They believe the firm has unloaded its troubled subsidiary rather than deal with its problems in a responsible fashion.

Scottish Power confirmed on Tuesday that it had agreed to sell PacifiCorp, which had failed to make earnings targets, to US energy firm MidAmerican for $9.4bn (�5.14bn).

About $4.5bn (�2.46bn) of the net proceeds will be returned to shareholders.

The news sent the company's shares up 27.75 pence, or 6.2%, to 469.75p.

However, watchdog energywatch Scotland has urged Scottish Power to share its profits with its most vulnerable customers.

Bad weather

Scottish Power bought PacifiCorp in 1999 for about $10bn.

It serves more than 1.6 million customers in the US, covering an area of about 136,000 square miles in areas including Oregon, Utah, Washington and California.

The US electricity producer accounted for about 50% of overall earnings but it had recently suffered from bad weather and power cuts at plants.

Last year, operating profits at PacifiCorp fell to �541.7m from �619.3m a year earlier, before accounting for exceptional items.

Scottish Power is now out in the cold as the only major energy supplier in Scotland that is not offering any relief for its hardest pressed customers Audrey Gallacher energywatch Scotland

"This was proving to be a difficult year for PacifiCorp," said Scottish Power chief executive Ian Russell.

Native American Indians insist hydro dams on the River Klamath in California have deprived them of their traditional fish supplies.

And they say the problem should have been solved by negotiation before PacifiCorp was sold on.

Scottish Power has maintained all along that it was willing to do what it could to save the salmon.

New buyer MidAmerican Energy is a Des Moines, Iowa-based unit of billionaire investor Warren Buffett's Berkshire Hathaway company.

The breakdown of the deal shows that MidAmerican is paying $5.1bn for PacifiCorp and assuming $4.3bn of its debt.

Vulnerable customers

The sale is expected to take between 12 months and 18 months to go through and is subject to the agreement of regulators and shareholders.

Scottish Power also reported that pre-tax profit before goodwill and exceptional items for the year ending 31 March rose 10% to �1.015bn ($1.9 bn).

That performance was driven by a 20% increase in UK customers, investments in generation, better efficiency at its UK network and further returns from its US wind and gas storage assets.

Audrey Gallacher, energywatch Scotland director, urged Scottish Power to share its good fortune with its most vulnerable customers.

"ScottishPower is now out in the cold as the only major energy supplier in Scotland that is not offering any relief for its hardest pressed customers," she said.

"Scottish and Southern Energy, British Gas as well as EDF energy introduced special funds or tariffs for their most vulnerable customers.