Unite the union has threatened to put a vote for industrial action to its members employed by DHL Supply Chain, unless guarantees are made over their pension schemes.

Both parties are currently in talks over changes to its different pension schemes: its final salary pension – which Unite alleges DHL wishes to close - and its defined contribution scheme called Voyager.

DHL also offers the government’s new auto- enrolment scheme.

Unite believes that with DHL not giving guarantees to the continuation of its Voyager scheme – which sees DHL contribute between 3% and 4% - over 16,000 employees could switch to the “less lucrative” auto-enrolment scheme.

Unite national officer for transport Matt Draper said: ““DHL is a highly profitable company and we don’t want to see them in the forefront of eroding retirement incomes in a race to the bottom that could act as Trojan Horse for other employers to follow in debasing pensions in the UK.

“We estimate that nearly 20,000 DHL employees could be adversely affected by these complex pension changes – and we will consider very strongly an industrial action ballot, if negotiations fail to achieve a fair and equitable settlement for our members.”

However DHL told Motortransport.co.uk that it had no plans to make any changes to the defined contribution Voyager pension scheme.

A spokeswoman for DHL said: “DHL Supply Chain is consulting with around 3,500 members of its defined benefit pension scheme and has no plans to make any changes to its Voyager defined contribution scheme, which has more than 13,000 members who are unaffected by this consultation.

She added that the remainder of employees had been automatically entered into “auto enrolment” and they were all were offered the opportunity to participate in the Voyager scheme on joining the company. She insisted that the scheme remains open to newly hired employees.

“To date we have made auto enrolment arrangements for 17,000 staff, who declined the opportunity to participate in the Voyager scheme. The consultation process will continue with individual affected employees and the trade unions in the coming weeks, when we hope to clarify any concerns raised,” she said.