A CROSS-party pledge to preserve Scotland’s higher public spending forever if it votes ‘No’ tomorrow (Thursday) triggered an angry backlash yesterday (Tuesday).

In what was branded a “desperate” bid to save the Union, David Cameron, Ed Miliband and Nick Clegg joined forces to vow to keep the infamous Barnett Formula.

The pledge – emblazoned over the front page of a Scottish newspaper – was an attempt to counter SNP claims that funding will be under threat if voters reject independence.

But the three leaders faced criticism that they were risking a backlash from taxpayers in England and Wales, where funding to Scotland is increasingly viewed as too generous.

The 35-year-old Barnett Formula has delivered Scotland £733 more per person than the much poorer North-East – a figure that has more than doubled from £361, in 2010-11.

Yet, Scotland’s gross value added (GVA) per head currently stands at 98.6 per cent of the UK average, while the North-East languishes at just 75.9 per cent.

As recently as March, Mr Clegg pledged a “top to toe look at Barnett”, once the nation’s finances had been stabilised.

And, just last week, William Hague admitted Scotland enjoys much better broadband than his North Yorkshire constituency because of its higher Government funding.

Yet, in their joint pledge in the Daily Record – two days before the referendum - the three leaders committed themselves to “the continuation of the Barnett allocation for resources”.

But the Hannah Mitchell Foundation, which campaigns for an elected Northern assembly, said the issue could not be ignored in any post-referendum devolution shake-up.

Professor Paul Salveson, the campaign’s general secretary, said: “At the moment, everything is up in the air and that must also include the funding mechanism.

“A look at the Barnett Formula, and how the regions are funded, is inescapable if the UK is going to stay together – there needs to be more investment in the struggling parts of England.”

One North-East Labour MP, speaking off the record, said: “After Thursday, there will need to be a really serious look at devolution to the regions and I think the Barnett Formula will be part of that.”

However, other Labour MPs, Tom Blenkinsop (Middlesbrough South and East Cleveland) and Helen Goodman (Bishop Auckland), said the crucial issue was now higher spending in London and the South – not in Scotland.

The joint pledge was also criticised by Tory MPs in the South. One said his voters would be “aghast if the unbalanced devolution from 1979 is made even worse”.

Critics protest that the Barnett Formula has enabled Scots to enjoy benefits such as free social care for the elderly and free student tuition that England cannot afford.