A London university has urged the UK’s University and College Union (UCU) to submit an alternative proposal for benefit reforms in the Universities Superannuation Scheme (USS) instead of industrial action.

Universities UK (UUK), the representative group for employers in USS, made a proposal that would see USS change from final salary to a hybrid scheme with career-average benefits.

Trade union UCU made counter arguments against the proposed reforms, attacking the statistical methodology, describing figures used during negotiations as “dodgy” and “misleading”.

Changes to the benefits structure at USS are expected to help repair an estimated £8bn (€10.1bn) deficit in the £41.6bn scheme, one of the largest in the UK.

The scheme is currently split between final-salary and career-average benefits – with new proposals to make all members career average for earnings up to £50,000, and defined contribution savings thereafter.

Balloted scheme members rejected the proposal, with staff at 69 universities in USS set to take up industrial action on 6 November.

University College London (UCL), a USS employer, described the industrial action as premature and told its employees UCU had been asked to submit an alternative proposal but had yet to do so.

The Union did submit a request to USS trustees to change the calculation of actuarial assumptions on the basis it did not share its “pessimistic” outlook.

However, the trustees refused.

Negotiations on changes to USS are being held by a joint negotiation committee (JNC) with representatives from the UCU and UUK.

The union was asked to submit its alternative proposal at or before the next committee meeting in two weeks, with negotiations concluded and a final propsal for USS Trustees by January 2015.

Nigel Waugh, UCL HR director, said the UCU’s notification of industrial action was premature.

“The UUK and UCU continue to negotiate on a way forward for keeping a core DB pension across the sector,” he said.

“No amount of industrial action will reduce the deficit of the fund, nor identify a panacea that does not include benefit change and contribution increases.”

The USS scheme reported positive investment results until the end of March, but its chairman warned that the triennial valuation would reveal deeply concerning figures.

The UCU said it would be consulting its branches on alternative proposals in the next week.