Opinion polls showed an increase in support for the Yes campaign as the referendum approached. On 8 September 2014, Gordon Brown set out plans for greater devolved powers for Holyrood in the event of a No vote. Lamont joined Ruth Davidson and Willie Rennie in giving her backing to the proposals the following day, but Salmond dismissed them as "a retreading, a repackaging, a re-timetabling" of previous promises. Prime Minister David Cameron and Opposition leader Ed Miliband cancelled their appearance at Prime Minister's Questions to travel to Scotland to campaign for a No vote. On 18 September, Scotland voted to reject independence with a majority of 2,001,926 to 1,617,989. Salmond announced his intention to resign as First Minister and SNP leader on 19 September, shortly after the result of the referendum was confirmed. Lamont paid tribute to him, describing him as "an immense figure in Scottish political history". Sturgeon was chosen to succeed Salmond as SNP leader on 15 October. Labour's Commission on devolution At the Scottish Labour Party Conference in March 2012, Lamont announced her intention to establish a Commission to examine the prospect of a fully devolved Scottish Parliament. This would give the Scottish Government the power to make decisions on policies relating to issues such as welfare benefits, income tax and corporation tax, effectively making it a fully self-governing region of the United Kingdom. The Commission, chaired by Lamont and including politicians, academics and trade union members, met for the first time in October 2012. It published an interim report in April 2013, recommending that Scotland have autonomy over income tax, but leaving decisions on corporation tax and welfare to the UK Parliament. But party members opposed it, warning that the plans could threaten the Barnett formula, the financial mechanism under which Scotland receives an annual average of £1,600 per head more in UK Government spending than does the rest of the UK. Ian Davidson, chair of the House of Commons Scottish Affairs Select Committee said the proposals could affect spending in poorer areas. Macintosh subsequently warned that devolving responsibility for income tax would reduce the Scottish tax base and result in independence by default, a claim that Guy Lodge and Alan Trench of the Institute for Public Policy Research called "highly disingenuous" because income tax makes up only 23% of the taxes collected by the UK Government. The Commission's final report, Powers for a Purpose was