Des Browne yesterday marked what Whitehall described as a step-change in Labour's attack on the Scottish Government with an all-out assault on Alex Salmond's "shoddy" and "ridiculous" administration.

Nicola Sturgeon, the Deputy First Minister, replied by dismissing the Scottish Secretary's broadside as a "bizarre rant", illustrative of Labour's panic at the SNP's rise in the polls to 40% support.

Last night, The Herald was told the Scottish Secretary's harsh words were the beginning of a political strategy to highlight what the UK Government has labelled "government versus grievance".

An insider explained: "The SNP's most important policy - local income tax - is nonsense, and while Westminster governs in the interests of Scotland, all they are engaged in is the manufacture of grievance. This is a step-change and you'll see more of this."

In a newspaper article, the Scottish Secretary accused the Holyrood government of trying to "foster grievance" with Westminster and paint it as a bully to divert attention from the SNP administration's plan for a local income tax (LIT).

This, Mr Browne argued, was so that Mr Salmond could "blame its likely failure not on those who designed it but on those the SNP demand should administer it". He wrote: "The propaganda exercise to support the myth that the SNP is the only level of government with any interest in Scotland is both demonstrably ridiculous and, from the evidence of this week, the central focus of their activity."

Mr Browne poked fun at the First Minister's visit to America last week where, he observed, Mr Salmond had been "comparing himself to Thomas Jefferson".

He added: "In the parallel universe that the SNP inhabit, everything the UK Government does is portrayed as either an act of betrayal or interference in Scotland."

The Secretary of State's attacked followed a week of cross-border skirmishing.

In London, John Swinney, Scotland's Finance Secretary, met Yvette Cooper, Chief Secretary to the Treasury, after she raised concerns of a £750m black hole in the Scottish Government's LIT plan.

Holyrood wants Westminster to hand over £400m-plus in council tax benefit to help run its proposed LIT replacement. The UK Government's message is: no council tax, no council tax benefit.

While Mr Swinney complained the Treasury was "not acting in an even-handed fashion towards Scotland", Mr Brown at his regular Downing Street press conference suggested it was ridiculous to claim Holyrood was being underfunded when it was getting nearly £30bn a year.