GORDON Brown has admitted the “Vow” has not been delivered – almost a year after he masterminded it.

Giving evidence to a parliamentary group at Westminster on devolution, the former Prime Minister expressed frustration at the process of handing over more powers to Holyrood, and said the Scotland Bill was falling short of the recommendations made by the Smith Commission.

His comments will ignite anger among Yes supporters, who suspected the move was a ploy by Unionists to stop Scots backing independence.

“The Government [is] falling short on the delivery of the recommendations of the Smith Commission on Scottish Devolution and the case for action is enhanced if the government is unwilling to listen to alternative views,” said Brown.

Brown was the architect of “The Vow”, which saw David Cameron, Nick Clegg and Ed Miliband sign a letter promising Scotland extensive new powers.

The letter, written on mock medieval parchment, appeared on the front page of the Daily Record two days before the referendum and has since become a notorious document among supporters of the Yes movement as support for independence has increased.

Last night, SNP MSP Linda Fabiani, who represented the SNP on the Smith Commission, said the “bogus” Vow would haunt Labour for years to come.

“That Gordon Brown and the Labour party played a key role in this bogus promise to people in Scotland – and campaigned side by side with the Tories throughout the referendum – will continue to haunt them until next year’s Scottish Parliament election and beyond,” she said.

“The fact that the powers promised have not been delivered means it is no surprise support for independence has risen – and it will continue to rise for as long as Scotland’s voice is ignored by an arrogant, out-of-touch Tory government we didn’t vote for.”

Patrick Harvie, MSP for Glasgow, added: “Gordon Brown’s admission confirms what the Greens and many others have been saying all along. The Vow was empty campaign rhetoric from political parties which would have promised people anything to keep them from voting for Yes. I doubt they ever had the slightest intention of taking the radical action it implied.

“The continuing strong support for independence shows that people are dissatisfied with Westminster rule. The feeble Scotland Bill is simply not enough, as we will continue to be vulnerable to the Tories’ ruthless austerity measures even after it finally comes into force.”

The Vow pledged to start the process of devolving the extra powers the day after the referendum, and established a timetable that would see draft legislation drawn up in January to be law within 2015.

The then-trio of leaders also pledged to protect the Barnett formula, which gives Scots an average of £1,200 per head more than the UK average of public spending, but said the new tax-raising powers would give Holyrood “the final say” on what is spent on the NHS north of the Border.

As well as promising new powers for Holyrood, the Vow also said it would “guarantee fairness for Scotland” and that the Union would work “to ensure opportunity” and the “social and economic welfare of every citizen”.

Brown’s comments were made to the All-Party Parliamentary Group for Reform, Decentralisation and Devolution in the UK.

A UK Government spokesman was not available for comment last night, but ministers have previously insisted the Scotland Bill delivers the Smith Commission’s recommendations.

A spokesman from the Scotland Office told The National last month: “The Scotland Bill delivers the all-party Smith Commission Agreement in full.”