THE SNP will try to exploit internal Labour divisions on Trident and cause such a headache for Ed Miliband that he will either opt to postpone renewal or cancel it if he becomes Prime Minister after the general election.

Bill Kidd, the party's chief whip at Holyrood and its leading anti-nuclear campaigner, also said the party's "red line" opposition to Trident in the next parliament could, however, still allow nuclear weapons to remain on the Clyde until 2030.

Kidd said there was no way to scrap the submarine-based nuclear deterrent immediately after the election and its removal from Scotland could take another 15 years.

He also said that in a hung parliament with a Labour government, the SNP didn't expect to strike a deal with Labour on non-renewal of Trident, as Labour's leadership was "thirled" to it.

Instead, the SNP will use internal Labour divisions over Trident to work against renewal.

Last month a CND survey of 73 Labour candidates found 50 opposed renewing Trident, suggesting many Labour MPs could rebel against renewal.

The SNP plan is the virtual opposite of last week's Tory claim that Labour would "barter away" Trident away in return for SNP support.

MPs voted in 2007 to extend Trident, but next year sees the crucial 'Main Gate' decision on whether to have three or four new submarines at Faslane.

Critics say renewal would commit the UK to spending £100bn it can ill afford, and the Commons vote on 'Main Gate' should be used to abandon Trident.

Kidd, co-president of the international Parliamentarians for Nuclear Non-proliferation and Disarmament group, said non-renewal remained a "red line" for SNP MPs.

However that did not mean the SNP would collapse a Labour government that wanted to keep Trident by voting down a Queen's Speech or budget.

Rather, as SNP deputy leader Stewart Hosie said last week, SNP MPs would vote against the allocation of money to Trident on an issue-by-issue basis.

Kidd said: "The idea is not to sink the Labour party as soon as we get to a budget. That would be a bit pointless. It's got to be issue-by-issue.

"There are a significant number of Labour candidates who are against Trident, and if the SNP goes into an arrangement - not a coalition - with Labour then one of the things we'll push for, along with ending austerity, is non-replacement of Trident.

"We're not going to be able to get rid of it straight away, that just can't be done. That's just promising people something that isn't going to happen. But [there is] non-replacement and cancellation of the Main Gate process.

"Hopefully non-replacement means it's impractical to keep it going for any great length of time, but it would go up until about 2030.

"You're talking about another 15 years before it became dangerous and started falling apart."

The Glasgow Anniesland MSP conceded the parties committed to axing Trident - the SNP, Greens and Plaid Cymru - would only have 60 MPs between them "on a good day", far short of a Commons majority of 326, but said Labour splits could yet finish off Trident.

"Labour is saying they're going to replace Trident. However our belief is that because of the internal problems they would have trying to force that through in the face of austerity, it's actually something they might want to park, at least for a while.

"If we can get a delay, that's a start as far as we're concerned of making a move on Trident."

Former Stirling Labour MP Anne McGuire said: "Now we can see the SNPs true colours. Nicola Sturgeon in the Leaders' debate in Aberdeen made crystal clear the renewal of Trident was what she called a 'red line' issue. Now Bill Kidd says the SNP isn't interested in getting rid of Trident until 2030 but instead is playing politics with Scotland's security."