I'm puzzled. There was an interview with John Swinney (SNP) on the Today programme this morning, much of which focused on whether the SNP would "hold the Labour party to ransom" over Trident in the event of its being in some kind of arrangement with a minority Labour government after the election. I gather that several of the papers are also talking in these terms.
Personally I wish Labour would drop Trident, but it seems to me that any future Labour government that wished to keep it could ask for support from the Tory opposition for that purpose, making SNP support on the issue unnecessary. Obviously the Tories could sit on their hands, but even if they abstained that would very likely be enough for Labour to get its bill to renew Trident through. Or would the Tories want to be seen walking through the lobbies to vote against the UK's nuclear deterrent, merely for reasons of party advantage? I don't think that would play very well in any subsequent election.
In other words, I don't see what the fuss is about. Have I missed something?
I wonder if actually they want to sound tough, without actually wanting to pass it...
All Labour really needs to do to lay this is to ask whether the Tories would refuse to vote for Trident's renewal in the event of a Labour minority government.