The site was part of Contego Cartons, formerly Nampak Cartons, which was bought by US food packaging group GPI in January. As well as the Gillingham site, the £91m deal included Contego sites in Leeds, Hoogerheide in the Netherlands and Portlaoise in Ireland, all of which are understood to be unaffected by the closure of Gillingham.

Unite has demanded an “urgent meeting’ with the company, which launched a 45-day consultation at Gillingam last Wednesday (5 June) where the union said it will urge the US owners to “to look at all possibilities for re-location and the best possible deal for the workforce”.

According to the union the company is proposing to close the facility on 30 September.

“This is a very difficult time for the workforce and they have a right to be angry that they face redundancy. Unite will be demanding the company does everything possible to support the workers affected,” said Unite national officer Ian Tonks

“At a time when unemployment is high and good jobs are hard to find, employers should be going out of their way to find the best deal possible for workers who have given years of loyalty.”

In an statement, Graphic Packaging International said that it had been reviewing its European manufacturing operations since the acquisition of Contego Cartons and AR Carton and while it praised the quality of the work produced at GPI Gillingham it said that the site did not fit in with its future requirements.

It added that it is currently consulting with the Unite and the Graphic Packaging Employee Information and Consultation Committee on the proposed closure.

In the statement, the company said: “These are always difficult decisions, but it is a necessary step in the company’s continuous efforts to effectively align and optimize its supply chain footprint. We do realise the impact of this decision on our team members; their families and their communities and we remain committed to providing assistance under our policies to help mitigate the impact of this decision where possible.”

The company added that work produced at Gillingham would most likely transfer to Leeds, however it said that business would continue as normal until then.

Graphic Packaging is a global packaging group with sales of $4.3bn and it employs 15,000 staff around the world, including locations in Australia, Brazil, Canada, China, France, Germany, Japan, Mexico, Spain, the UK and the US.