Scottish Labour leader Anas Sarwar had challenged Mr Swinney to “re-examine his red lines” in relation to defence, stressing the importance of this to “ensure we are never at the mercy of dictators like Putin”.

The Labour leader made the plea a week after former SNP Westminster leader Ian Blackford had challenged his party to move away from supporting unilateral disarmament for the UK.

But the SNP leader was clear, saying: “Mr Sarwar knows my position on the nuclear deterrent. I don’t believe nuclear weapons should form part of the defence approach that we take forward.”

The First Minister added: “What we need to have to ensure we can repel Russian aggression is to have effective conventional forces.”

Swinney stressed: “I think it is important we have the defence forces and requirements that are necessary for our times, and I would simply point out to Mr Sarwar there are nuclear weapons that are held by a number of countries now and it has not stopped the conflict that is taking place in Ukraine at the very moment.”

His comments came as Sarwar warned that the world was becoming “increasingly dangerous”, insisting that SNP policies – which reject both nuclear weapons and nuclear power – are impacting on Scotland’s energy security and its national security.

Raising the issue at First Minister’s Question’s at Holyrood, Sarwar said: “At a time when there is a war on our continent and the world is increasingly dangerous, the SNP’s position is we give up our nuclear deterrent now while countries like Russia hold on to theirs.”

The Scottish Labour leader told Swinney: “This is not the time for rigid ideologies but for serious, pragmatic leadership.

“Keeping our country safe should be the first priority of any government, but isn’t it the case that whether it is on economic security, energy security or national security, the SNP’s policy would make our country less safe and less secure.”

He also argued action is needed to ensure the defence sector – which is worth more than £3bn-a-year to the Scottish economy and supports 33,000 jobs – has the skilled workers it requires.

But as it stands Sarwar said: “The reality is much of the skilled labour in Scotland’s defence industry is coming from abroad on temporary contracts, because we’re not equipping Scots with the skills they need.”

At this “generation defining moment”, the Labour leader stressed all leaders must “examine previous red lines”, as he accused the SNP of being “at best uncomfortable and at times hostile” to the defence sector.

Swinney, however, stressed the Scottish Government was working “closely with employers” to help ensure Scotland has “the skills that are necessary for the 21st century.

He told MSPs that deputy first minister Kate Forbes had met representatives from the sector, including shipbuilders BAE, to discuss the issue of skills .

The First Minister said: “These are discussions the Government is engaged with. It is part of our duty to ensure the country is secure and is safe.”