Ed Miliband has expressed his sorrow at the loss of more than 500 jobs at the Lynemouth aluminium smelter.

Northumberland’s biggest private sector employer, Rio Tinto Alcan, announced it would close the smelter, blaming rising energy costs.

The firm will now conduct a 90-day consultation process with staff and union representatives.

There are also fears over a further 100 jobs as the company also revealed it is in discussions regarding the potential sale of the power station at the site.

The Lynemouth smelter opened in 1972 and employs 515 people. An additional 111 are employed at the power station.

Mr Miliband said: "It’s very bad news about what is happening at Alcan and I am very sorry for them and for their families.

"We said very clearly we would cut VAT, which would give some relief in relation to fuel costs, for instance. But the most important thing to say is that unless we get our economy moving we are going to see more redundancies and that is the problem."

Mr Miliband was visiting the Sunderland works of crane manufacturer Liebherr as part of Labour’s campaign for jobs and growth today.

He added: "So let’s get our economy moving. Let’s not stick to a rigid idea that what the Government was trying to do 18 months ago, which isn’t working, is what we should stick to now.

"We should change course.

"Things can change but it requires action by a Government that is willing to change course."

A statement from the firm said the smelter was "no longer a sustainable business" because its energy costs were increasing significantly, largely due to emerging legislation.

Rio Tinto CEO Jacynthe Cote said the company hoped the power station would remain in operation under new ownership.

She said: "For 40 years, the Lynemouth smelter and power station have been important parts of the community and we will work with our employees and other key stakeholders to ensure that the social and environmental consequences of today’s announcement are managed in the most sensitive way.

"We are also committed to supporting local initiatives to identify and develop alternative opportunities that promote regional economic development. Finally, we will also continue to support our valued customers."

The news comes after the county council said 10 days ago it was preparing for the worst over the future of the two operations.

It is thought the smelter and power station support a further 3,000 indirect jobs across the region.