A union leader says he is "not optimistic" that strike action can be avoided at Sellafield in a row over pensions.

Len McCluskey, the general secretary of Unite, visited West Cumbria yesterday to address Sellafield workers, and listen to their concerns over the "disgraceful" changes proposed to their Nuclear Decommissioning Authority (NDA) pensions.

"What's being proposed is daylight robbery," said Mr McCluskey, who is currently seeking re-election to the union's top job. "It would rob highly-skilled, hard-working people of a healthy pension fund, and break promises given to them by the previous government."

The strike threat appears to have been put on hold after unions Unite, Prospect, GMB and ASLEF/TSSA, held a "constructive" meeting with Energy Minister Jesse Norman which has led to a delay in a strike ballot being called. Further talks are now planned.

The changes to final-salary pensions, proposed by the NDA across its whole estate, are aimed at saving £660 million. Nationally, it affects 11,000 workers at 19 sites including Sellafield, the Low Level Waste Repository near Drigg, and International Nuclear Services at Westlakes Science Park. A consultation period with workers ends on March 10, and the NDA says the aim "is to make public sector pensions fair and to put them on an affordable and sustainable footing."

Speaking to the News & Star following the gathering of workers at Egremont Cricket Club, Mr McCluskey said: "I welcome the fact that there is going to be further talks and I hope they'll be productive, because at the moment, what is happening is just plain wrong.

"The government has offered two options; neither of which are acceptable as they involve workers paying in more yet getting a lesser pension. Therefore, we are calling on the government to step back from these proposals, or there is every likelihood that it will end in industrial action.

"The staff are doing an essential job for the country, yet their futures are being attacked. We, as a union, will resist and repel these attacks."

Unite has between 1,700 and 1,800 members at Sellafield. John Tear, union convenor on site, added: "Members welcomed Mr McCluskey's stance on changes to workers' pensions and terms and conditions.

"The proposals are disgraceful. The pension fund is not in deficit; when it was last reformed in 2008, the scheme was closed to new members, so it has become a finite fund, so why attack it?"

Unite members will vote in the general secretary election between March 27 and April 22. Mr McCluskey has held the position for six-and-a-half years.