Both have been at the sharp end as companies closed and unemployment rose but while the Prime Minister’s popularity continues to fall, support for Mr Salmond remains strong.

An opinion poll this week shows almost half the electorate think anyone would do a better job than Mr Brown as Labour leader, while a poll earlier this month showed 32% of Scottish voters backed Mr Salmond as First Minister, compared to just 12% for Scottish Labour leader Iain Gray.

Mr Salmond’s grip at the top of the SNP is unassailable and the polling shows the nationalists ahead of Labour in both Holyrood and Westminster voting intentions.

Both men are presiding over economies struggling to cope with the effects of the recession but people believe the buck stops with the PM, despite his efforts to shore up the banks and, at the G20 summit in London earlier this year, orchestrating a global plan for recovery and reform in what many observers believe was his finest hour.

In contrast, and despite large-scale job losses at Diageo, Bausch and Lomb, Hewlett-Packard, the banking sector and others, Teflon Eck seems largely unscathed.

He is able to claim the big levers of power lie in London, an argument that appears to be keeping many people on his side rather than being seen as an excuse for the Scottish Government’s failure to save jobs.

The next test of Mr Brown and Mr Salmond’s popularity will be the Glasgow North East by-election, expected in November, where the SNP will be hoping to repeat last year’s coup in Glasgow East. However, the Labour Party is better prepared this time and through former MP Michael Martin and his MSP son, Paul, have a well-established grip on the constituency.

If the polling trends continue on their present course, however, and are translated into actual votes at next year’s General Election, Labour is faced with losing seats to both the SNP and the Conservatives in Scotland.

Some of its big names, such as the Chancellor Alistair Darling and Scottish Secretary Jim Murphy, will have to fight very hard to hold on to their constituencies.

While this is going on in Scotland, Tory leader David Cameron is gaining momentum across the UK by saying the right things on subjects like MPs’ expenses but giving little away on policy details.

Not only is he now favourite to win the election, the most recent polls indicate he will have an overall majority.

It will be a confirmation of the saying “Opposition parties don’t win elections, governments lose them”.

The LibDems, in the meantime, continue to struggle to make progress. Their leader, Nick Clegg, has been overshadowed throughout the recession by very able performances from Vince Cable, the party’s Treasury spokesman.

In Scotland they could be under pressure from the SNP in Argyll and Bute and from the Tories in Berwickshire, Roxburgh and Selkirk.

Long-term trends show that when confidence in the Labour party’s handling of the economy slides, the “don’t know” voter group shoots up. The Nationalists now believe there are no no-go areas. And in Scotland, when Labour is in trouble, the principal beneficiaries are the SNP.