The owners said the site was too expensive to run in its present form.

But many workers are angry that the company turned down £48M from the UK and Welsh Assembly Governments to keep its business going. A union representative said work prospects for the 390 people losing their jobs in one of the UK’s most deprived areas were ‘very bleak’.

Joint owners Rio TintoGroup and Kaiser Aluminium decided to close after failing to secure a discounted energy deal, despite being offered aid. Between 80 and 90 staff will be kept on to maintain the site where the company will start remelt activities of about 60kt/y.

The plant on the outskirts of Holyhead uses 12% of the total electricity used in Wales. Its history has been closely tied in to an energy deal with the nuclear power station at Wylfa, 14 miles away. But the station is due to be decommissioned and there had been concerted efforts to secure the aluminium plant’s future.