Trident is currently based at Faslane on the Clyde
The SNP has joined forces with Plaid Cymru on the UK election campaign trail to set out their opposition to Trident nuclear weapons.
The Nationalists called for the replacement system to be scrapped, saving billions of pounds.
Meanwhile, Labour asked the public to support its plans to jail knife carriers for six months, while the Lib Dems focussed on saving post offices.
The Tories were campaigning in Angus, one of their key target seats.
Speaking at an event in London, SNP Westminster leader Angus Robertson, who was joined by Plaid's Adam Price, said they offered an alternative to the pro-Trident stances of the UK parties.
Mr Robertson said: "Renewing the Trident nuclear weapons system will cost £100bn over the next 20 years - it cannot be right that we proceed with its procurement whilst simultaneously cutting funding for schools, hospitals and frontline services and putting the recovery of our nations at risk."
Annabel Goldie and Andrew Mitchell met candidate Alberto Costa
UK Conservative international development spokesman, Andrew Mitchell, who was campaigning with Scottish Tory leader Annabel Goldie, said David Cameron and Gordon Brown were in agreement on Trident.
He added: "The Labour Party now agree with us about Trident and the importance of this element of our national defence - and that is a good thing.
"The effect of the SNP policy on this matter will be to lose 11,000 jobs in that very important area in Scotland and we do not want to see that happen."
The Scottish Liberal Democrats said they may support a nuclear deterrent, but said they would not back a like-for-like replacement of Trident.
The Lib Dems say they saved Kelvindale Post Office from closure
Meanwhile, Scottish Labour leader Iain Gray was joined in Glasgow by a group of his MSPs, asking shoppers at the Fort Shopping Park to back the proposals.
He claimed knife murders in Scotland were more than double the rate of the rest of the UK and cost the NHS more than £500m last year.
Mr Gray, who was campaigning with Glasgow East candidate Margaret Curran, said: "It's time that politicians from other parties woke up and looked at what is happening out on the streets of Scotland and realised that continuing to do nothing is no longer an option."
The Labour Party wants people to back its knife crime policy
Scottish Lib Dem leader Tavish Scott hit out at Labour's "decimation" of the Post Office.
He was campaigning in the target seat of Glasgow North with candidate Katy Gordon, where he claimed the Lib Dems had saved Kelvindale Post Office from closure.
Mr Scott, said: "Scottish Labour MPs stood by and did nothing while the UK Government decimated our Post Office network."
There is now two weeks left to polling day on 6 May.