Union leaders have stepped up their campaign to save a Cadbury factory threatened with closure after publishing an internal memo showing a huge increase in the company's sales in the UK.

Unite said last night that the message revealed a 15 per cent increase in sales in October which the union claimed proved it was "unnecessary" to close the factory at Keynsham, near Bristol. The company is planning to switch production to Poland in a move which has angered unions and the local community.

Unite said the memo "blows apart" the argument for closing the factory. National officer Brian Revell said: "This memo reinforces our belief that Cadbury is acting like a private equity company and pandering to shareholder greed.

"There is no case to close Keynsham and move to Poland - it is wrong on business and environmental grounds. The Polish unions don't agree with it, the workforce doesn't agree and neither do the local communities."

As part of the campaign, workers from the Keynsham plant will join colleagues outside Cadbury's Bournville factory today to promote the Keep Keynsham Cadbury's protest march on Saturday.

A coachload of Keynsham workers, led by Unite convenor Andy Nicholls, will hand over a letter thanking fellow Cadbury workers for their support. They will also hand out leaflets promoting their campaign and the protest march.

"Cadbury bosses need to know their workers, consumers and local communities oppose the sacking of half the UK workforce and the environmental havoc of transferring work to Poland," said Mr Nicholls.

"Bournville and the other Cadbury plants at Chirk and Marlbrook have made common cause with Keynsham to march this Saturday. Cadbury should be ashamed of what they are doing and reverse their decision now."