Not so long ago, the Labour Party had the appearance of being Scotland's political establishment.

When the Scottish Parliament was created, in 1999, they had 56 out of 72 Scottish MPs and a virtual monopoly of local government.

Lord Ashcroft's poll of 16 Scottish constituencies shows that the party's support has melted like snow in spring.

His first round of constituency research suggests that not a single Labour seat is safe from the Scottish National Party (SNP). The party is trailing in areas that it once regarded as its heartland including Glasgow, West Dunbartonshire and North Lanarkshire.

Significantly, these are also the places where the Yes vote was highest in September's referendum on Scottish independence.

Until recently, many Labour insiders were confident that the SNP's lead in the polls would shrink as polling day got closer. The looming prospect of a second Conservative term in office will bring them home to Labour.

With less than 100 days to go there is no sign of this happening.

Instead, it looks like the unprecedented level of political engagement with the referendum has pushed many voters to permanently switch their allegiance to the SNP.

By campaigning alongside the Tories, Labour defined itself as part of the establishment when there is an anti-establishment revolt going on right across Europe.

In England, the desire for a change in the way politics is conducted is expressed in record support for the Greens and UKIP.

Furthermore, four years of coalition government has conditioned the media to multi-party politics.

This complex new reality has already been recognised by the broadcasters who have invited the SNP to take part in televised debates for the first time. If they go-ahead, SNP leader Nicola Sturgeon will enjoy a much bigger media profile during the campaign.

All of this makes it far harder for Labour strategists to define the election as a two horse race between Labour and the Conservatives.

If the SNP succeed in replacing Labour as Scotland’s dominant party at Westminster they could hold the balance of power.

It means that just a few months after losing the vote on Scottish independence, the Nationalists would be in a position to decide the future of the whole of the UK. Former First Minister Alex Salmond once described it as making Westminster dance to a Scottish jig.

The price of any deal would be the transfer of much greater powers to Edinburgh and a further fraying of the UK’s political unity.

Follow Andrew McFadyen on Twitter @apmcfadyen

Source: Al Jazeera