Workers at consumer goods giant Unilever, including a site at Leeds, will stage a protest outside the firm’s London offices in a worsening dispute over pensions.

The move follows a decision at the weekend to call a series of strikes at factories across the country, for up to 12 days starting on January 17.

Workers held a one-day strike last year in protest at the ending of Unilever’s final salary pension scheme.

Unilever workers from sites at Purfleet, Port Sunlight, Warrington, Leeds, Crumlin, Gloucester, Manchester, Burton-on-Trent and Chester say they are fighting an "unjustified" attack on their pensions.

Unions said the stoppages will hit production of the global giant’s leading brands, including Dove, Marmite, PG Tips, Pot Noodle and Hellman’s Mayonnaise.

Unite, the GMB and Usdaw say the company’s plans to axe the final salary pension scheme will see the retirement income of thousands of staff slashed by up to 40%.

Speaking ahead of the demonstration, Unite general secretary Len McCluskey said: "People are fed up to the back teeth of big businesses growing fatter and bigger still, not on hard graft or enterprise, but by hitting the savings plans of their workforce. The Unilever workers are standing up for themselves and they have right, and their unions, on their side.

"This is yet another black mark against the behaviour of FTSE companies. Here we have the 18th richest company in the world dipping into the pension plans of workers in towns across the UK.

"Given that the pensions scheme is funded and healthy, Unilever’s raid on the workers’ pensions is nothing other than bare-faced greed. Why else is the company refusing to talk to us? It must surely be because it is ashamed about the base nature of this snatch.

"We sincerely hope that the shareholders can talk some sense into this company and at least get them to meet us at Acas."