Hundreds of jobs are under threat following proposals by 300-year-old English tea company Twinings to move the bulk of its production overseas.

The Associated British Foods company announced this week that it planned to move 75% of Twinings' manufacturing from plants in Andover and Newcastle to China and Poland.

The move, scheduled for 2011, could result in the closure of Twinings' tea-packaging factory in Newcastle with the loss of 263 jobs. Another 130 jobs could go at Andover following the installation of automated packaging equipment.

The Twinings tea drunk in the UK would not be affected, insisted Twinings international supply director Marcus Cotter-Stone, as 25% of the manufacturing would remain here. Only exported tea, which at the moment accounted for two thirds of Twinings' business, would be produced overseas, he said.

Relocating production to China and Poland would improve sustainability, he added. "Currently, we buy bulk tea from China, India and Africa and ship it to England where it is packaged and then exported back all around the world. It's just not a sustainable approach," he said.

While Cotter-Stone claimed the English image of the brand would not suffer, Mike Parsonage, Usdaw organiser for the Andover plant, predicted that export sales would struggle.

"It is sold as an English product. Once consumers are aware that the tea is produced in Poland they will lose sales," he said.

ABF this week posted a 12% increase in group revenues to £9.3bn for the year to 12 September.