UNITE leadership contender Gerard Coyne has said the union will take a harder line in support of retaining Trident if he defeats Len McCluskey in the contest,

Speaking exclusively to the Sunday Herald, Coyne claimed the Clyde-based weapons system was about "preventing warfare" and was a "vital" part of the UK's defence industry, stating his uncompromising support for keeping nuclear missiles at Faslane.

However, Coyne's pro-Trident intervention, in his first interview with the Scottish media, came under fire last night from both SNP and Labour politicians.

Coyne said under his leadership Unite would not give "anything away without negotiating over it" as he set out how the UK's biggest union would harden its position in support of nuclear weapons.

In a sign of the growing bitterness in Unite's leadership contest, Coyne claimed McCluskey had failed to properly campaign for Trident and speak out in support of its members employed at the base.

Unite has sought to protect the jobs of workers at Faslane, but has not been wholly supportive of nuclear weapons under McCluskey's leadership.

Coyne accused his rival of being "confused" on the issue and dismissed suggestions Trident missiles could be deployed without their nuclear warheads, stating: "Who makes pencils with no lead?"

He said that defending the jobs of Unite members would be his priority if he is elected general secretary.

Coyne, a West Midlands Unite official, said: “Of course a world without nuclear weapons would be a better place. But we have to be realistic about the world we actually live in. I’ve never given anything away without negotiating over it.

"My first concern as general secretary would be our many members in the vital defence industry, particularly in Scotland. Unite members don’t understand why they have to defend their jobs when they are working hard to defend us all.

"I’m concerned that Len McCluskey has looked rather confused over this issue. For example just one year ago he was open to the idea of subs without missiles. Who makes pencils with no lead?

"I think we need to be clear – in the end Trident is about preventing warfare not providing welfare.”

However, the SNP's trade union spokesman Chris Stephens accused Coyne of making a "bizarre statement" about warfare and welfare, which he said was insulting to the unemployed and benefit claimants.

He also claimed Trident was a political weapon rather than one of defence.

The Glasgow South West MP also disputed Coyne's claim that scrapping Trident would destroy jobs.

Stephens said: "The suggestion that Trident is about preventing warfare and not about providing welfare is a bizarre statement and an insult to those who are suffering under the real impact of Tory austerity.

"Trident is not a defence weapon it is a political one. Neither does it provide better defence. Budgets for defence spending are being squeezed with the result being that the Royal Navy has fewer conventional ships than ever before. This has a real impact on shipbuilding in Scotland."

Adding: "The fact remains that there is no financial, moral or defence case to renew Trident. Diversification will create more sustainable and secure jobs if the industry is not dependent on one source of work."

Labour MSP Neil Findlay, a Unite member, warned Coyne against seeking to impose his pro-nuclear weapons stance on union members.

He said "It is concerning that a candidate for general secretary of Unite does not appear to fully understand that Unite is a democratic trade union where lay members determine the union's policy on Trident and all other issues.

"Those same lay members have developed a policy which recognises the dangers and economic issues around nuclear weapons, but also strongly defend members' jobs whilst seeking a firm and credible defence diversification plan.

"I may have my own personal views about Trident but I am pleased that in Len McCluskey we have a general secretary who recognises his obligation to present and defend the policies determined by the union's members."