Giant industrial structures, which dominated the Northumberland skyline for nearly four decades, were one step closer to destruction this week after owners applied for permission to demolish.

The Alcan aluminium smelter near Lynemouth was mothballed in 2012 with the loss of 512 jobs but its eight 80-metre chimneys still stand.

Now owners Rio Tinto have started the paperwork to tear them down as negotiations with potential buyers near completion.

But site spokesman John McCabe said the application was a formality to make sure the work could start quickly if a new owner wants it done.

He said: “This is the right thing to do in order to keep options on both sides open. We don’t want to take down a building which somebody needs but nor do we want to leave a building in place that is actually getting in the way of further development. We are in an advanced stage of discussions with interested parties and we hope to confirm who will be acquiring the site in the coming weeks.”

Mr McCabe said the company wants to find a buyer who will bring jobs back to the site and manage it in a “responsible and sustainable” way.

Wansbeck MP Ian Lavery called the chimneys a “Northumberland treasure” and said it would be a “sad day” if they disappear.

He said: “I use the flight from London quite regularly and I know I’m home when I see, out the window, St Mary’s Lighthouse and the Alcan chimneys.

“It’s the sign of a once top-class employer and the last of the remaining industrial landmarks, which, combined with the coal industry, supplied 3,000 jobs which we’ve struggled to replace.

“We’ve dusted ourselves down and looking forward and trying to create industry in other parts of south east Northumberland which should replace those jobs. It’ll be a difficult path, but we have no option.”

He said the area had never recovered from the “devastating” shut down, which “could and should have been prevented”, but claimed SMEs were “springing up” to fill the gap.

Rio Tinto organised CV workshops and interview coaching for its workers as well as donating a £630,000 ‘legacy fund’ to local projects.

Mr McCabe said 90% of the workforce had since found new jobs, become self-employed, retired or gone into full-time education.

But Mr Lavery said many new jobs in the area were lower-paid and less secure than Alcan posts had been.