Britain's biggest union, Unite, has vowed to do everything possible to defend jobs at the Pilkington Glass manufacturing site in St Helens, Lancashire.
The company has announced plans to close the Cowley Hill site with the loss of 140 skilled manufacturing jobs.
Unite Assistant General Secretary Tony Burke said:
There are thousands of manufacturing workers up and down the country who will be wandering what David Cameron and George Osborne mean when they talk about a recovery.
Valuable manufacturing jobs in steel, shipbuilding and now glass continue to haemorrhage while the government does next to nothing to support the sector.
"Unite will be meeting with Pilkington management over the coming days and we will be scrutinising the company's proposals to cut 140 skilled jobs.
– Unite Assistant General Secretary Tony Burke
The union will also be meeting the workforce to listen to their views on this terrible announcement.
These are skilled manufacturing jobs and we will be doing as much as possible to mitigate the impact on the workforce.
Pilkington Glass is closing a factory in St Helens with the loss of 140 jobs.
Pilkington said that, following a business review, it had decided to end manufacturing at its Cowley Hill float site in St Helens, Lancashire.
A company statement said: "The current economic downturn has impacted severely on float glass volumes, resulting in overcapacity, reduced prices and lack of profitability in the float product segment for the company in the UK.
As a result, a decision has been taken to adjust production capacity to match profitable customer demand."