SNP MPs have accused a defence minister of "offensive" claims the party is using safety concerns over Trident merely to oppose replacing the nuclear deterrent.

Penny Mourdant accused the SNP of exaggerating the potential effect of incidents because of its objection to the ageing weapons system on the Clyde.

During a debate in Westminster Hall, she told Rutherglen and Hamilton West MP Margaret Ferrier: "The level of concern that the hon. Lady expresses is disproportionate to the incidents-I think that comes down to her party's objection to the deterrent full stop."

She added: "Focusing disproportionately on safety-the incidents are in the public domain, so I can clearly show what they were, how meticulously they were recorded and the "lessons learned" programme that followed-does those who support Operation Relentless a grave disservice.

"These are incredible men and women who, whether they are on the submarines or part of the support and logistics operation, do an incredible job.

"One thing that I object to about the hon. Lady's line of argument is that it does those people a disservice.

"If the issue is whether we should have nuclear weapons, I hope the hon. Member for Rutherglen and Hamilton West will focus on that."

Carol Monaghan, SNP MP for Glasgow North West, said she was "hugely offended by what we heard, of being accused of being anti-Armed Forces. It is disgusting language to use."

Ms Ferrier said that she would be writing to ministers.

She warned a serious accident involving the convoys used to transfer warheads along the M74, through Glasgow, could be catastrophic.