We fight not for ourselves, Scottish Labour leader Jim Murphy will argue today, but for working class Scots who need a champion against the Tories.

But should the party persist with this strategy north of the border? The repeated insistence that every SNP MP elected will help return David Cameron to Downing Street to some appears to show a party which is very much fighting for itself - seeking the Scottish support Labour needs to return to Government without addressing Scotland's needs.

Meanwhile Ed Miliband is to highlight the cuts he believes will be facing Scotland if the Conservatives are re-elected in May.

But there are perils in this approach too. It replicates the very arguments the party insisted were scaremongering when they were made by those arguing for a Yes vote in the referendum - the fear that cuts to the NHS south of the border could undermine the ability of Scotland to protect its own health service.

Labour must clarify its message. Should Mr Miliband rule out the possibility of a deal with the SNP after May's poll, even if the outcome of the vote makes one workable? This might undermine Nicola Sturgeon's claim that voting SNP can deliver a strong and influential Scottish bloc at Westminster.

However Jim Murphy is said to be concerned that rejecting any deal could alienate some of the 193,000 former Labour supporters who voted Yes in the referendum, whom he is trying to woo.

The hope for Mr Murphy lies in the fact that many such voters still identify themselves fundamentally as Labour supporters. Unfortunately they say this before explaining that they have switched to a rival, or voted Yes in the referendum.

How can Mr Miliband and Mr Murphy counter this? The hope lies in that first statement.

If they were Labour once, can either leader persuade them to be so once again? Surely not if the current strategy is pursued. There is little evidence that a campaign warning that an SNP vote will let the Tories back in is gaining any traction.

It may be time for a rethink. The irony is that the party has a story to tell about its policies, many of which would seem on the surface to address many of the priorities which have seen support for the SNP soaring, and which saw Labour supporters defecting to Yes in September.

The SNP has been effective in insisting that there is little between Labour and the Tories but this is not the case. On the mansion tax, the reinstatement of the 50 pence tax band, the energy price freeze, and bankers' bonuses, for example, Mr Miliband's policies drastically differ from David Cameron and George Osborne's agenda.

In warning voters of the supposed dangers of a vote for the SNP, Scottish Labour can seem almost to be threatening them, and the question of a possible post-election deal is something of a distraction. But by spelling out their alternative to coalition austerity, Mr Miliband and Mr Murphy could get on the front foot and spell out the real policy choices on offer to voters.