UNIONS have urged a chocolate bar maker to freeze any changes to a pension scheme, fearing workers could lose thousands of pounds in retirement cash.

Unite and GMB have challenged Nestlé’s proposals, which would affect all 7,600 members of its UK pension programme and many of the company’s 2,700 staff based in York and Newcastle.

The unions say any changes should be held until a proper valuation of the scheme is made in December.

Nestlé proposes to close the defined benefit pension scheme, commonly referred to as a final salary pension scheme, and replace it with a defined contribution scheme.

The KitKat and Yorkie maker introduced the option of a defined contribution scheme for employees in 2010, while continuing to offer a defined benefit scheme.

However, earlier this month it revealed it was looking at changes due to costs.

But, in a letter signed by Julia Long, Unite national officer for the food and drink sector, and Stuart Fegan, GMB national officer for the manufacturing sector, the unions said: “We are aware an actuarial valuation of the scheme is due to take place in December.

“This would provide us a more informed position on the health of the scheme and be the logical point to discuss what actions may be required from all stakeholders to maintain the sustainability of it.

“We believe Nestlé is acting in a precipitous manner.”

The unions also argue Nestlé can afford to maintain the present pension scheme, as it is making increasing profits in the UK and international markets.

The letter added: “The company has placed the sole part of its case on the current economic position, rather than sufficiently evaluating what Nestlé could lose by making these changes.”

In response, a Nestlé spokeswoman said: "Nestlé UK has proposed the closure of its defined benefit scheme because, regrettably, it is not financially sustainable.

"The costs and risks of providing past and future pension benefits have increased far more than anyone could have predicted.

"The pension fund had a deficit of £850m at the end of 2014, despite the company contributing over £600m in additional payments to reduce the deficit in the last few years.

"We are very sorry we have to propose these changes but we believe they are necessary under the circumstances.

"We are committed to an open and meaningful consultation, and we will certainly consider all suggestions and proposals from our employees and their representatives.”

There are 620 people employed on the Nestlé site at Fawdon, Newcastle, where brands including Rolo, Munchies and Toffee Crisp are produced, and 2,115 people at York, where KitKat, Yorkie and Aero are produced.