And John Pugh, Liberal Democrat MP for Southport, said: “I’m appalled, but not surprised.

“For a long time, we have known that the formula works to our detriment and means infrastructure projects either cost us more, or simply don’t get built. The way all governments put off looking at the Barnett Formula is becoming a scandal.”

Anger has grown because Scotland, in the last financial year, received £9,179-per-head from the Treasury, while the North West figure was just £8,247 – a staggering £932 lower.

Yet Scotland is much richer. Income-per-head north of the border was 95% of the national average in 2006. In Merseyside, it was a pitiful 73%.

Meanwhile, the Scottish Parliament – thanks to higher funding from London – has announced eye-catching plans for free prescriptions, free eye and dental checks, a cut in class sizes in primary schools and a cut in business taxes.

Now the £500m for the new Forth Crossing has been handed over because any big spending commitment in England delivers a “Barnett consequential” for Scotland.

When the Government pledged £5bn to the Crossrail project in London, Scotland was automatically handed £500m – while the English regions received nothing.

Mr Murphy pointed to the Forth Crossing as a tangible benefit of the Barnett Formula when he gave evidence to the current Lords inquiry into the funding rules, a transcript of which has been released.

He told peers: “The read across from that number one transport investment in London [Crossrail] to the number one transport investment in Scotland would be the Forth rail crossing. It is now confirmed.”