The site in Haughley Park, near Stowmarket, has been labelled as unsustainable by the owners, 2 Sisters Food Group.

A spokesman for the company said the news would ‘not have come as a shock’ to workers who will be starting consultation talks with their employer.

But the union Usdaw, which represents about half of the workforce, said recent changes to the management structure had come “too little, too late”.

Adam Skwierawski, area organiser for Usdaw, said the factory “could have been turned around” if the new managers had been installed earlier.

He said: “Obviously everyone is gutted, the members are gutted and we are concerned about what the future is going to bring. It’s heartbreaking to see these skilled jobs disappearing.

“We are continuing to be in dialogue with the company to reduce the impact on our members. The early indication is that the company will deal with this in an amicable way.”

But Nick Murray, spokesman for 2 Sisters Food Group, said: “This has not got to with the personalities at all or the individuals – it’s got to with the site – it’s really ageing and not fit for purpose.”

He said the company, which has other sites in Thetford, Eye, Flixton and Witham, would look to redeploy staff at those locations.

Olivier Goudineau, divisional managing director for the company, said: “We are totally committed to producing the highest quality food for consumers in a sustainable and environmentally responsible way.

“Sadly, Haughley Park is an ageing site with many challenges and it does not enable us to fulfil our commitment to sustainable manufacturing.

“Our immediate priority now is to have meaningful discussions with our colleagues during this consultation period to see if other solutions can be found.”

The site employs about 440 workers with 250 being agency workers.