LONDON (Reuters) - Former British Prime Minister Gordon Brown said he would spearhead a push for Scotland to gain more powers within the United Kingdom if Scots reject independence in a referendum this month.
Brown, a Scot who represents a Scottish constituency, has returned to frontline politics to campaign for the 307-year old union with England as polls show pro-independents gaining ground ahead of the Sept. 18 referendum.
He said the devolution of power set in train by his 1997 Labour government with the establishment of a Scottish parliament was unstoppable, with proposals to allow more autonomy in areas such as tax supported by all main parties in Westminster.
"The status quo is not now an option. A 'no vote' does not mean no change, a 'no vote' will usher in further constitutional reforms in social, economic and fiscal affairs," he said in a speech in London.
"And a 'no vote' will mean the choice is against separation but for further devolution of power to the Scottish parliament."
Opinion polls show support for Scottish independence, led by Alex Salmond's Scottish National Party, at its highest ever level. A YouGov poll on Tuesday put the unionist campaign just six points ahead as support for independence jumped to 47 percent in August.
Brown, who was finance minister for a decade from 1997 before serving as prime minister for nearly three years, said he would lead a debate when parliament returns to secure the timetable on the delivery on further devolution proposals.
He said the four countries of the United Kingdom had achieved a closer union in terms of social justice and equality than any other grouping of countries or state in the world, for example by sharing resources in the provision of pensions, social security and healthcare.
"We are no longer a uniform, unitary state, we are a group of diverse nations who are in partnership...that champions power sharing as well as risk sharing and resource sharing," he said.
Brown's speech, to Labour supporters in Westminster, was designed to counter Salmond's argument that an independent Scotland could provide a fairer society.
"Scotland is one of the richest countries in the world, wealthier per head than France, the UK and Japan," Salmond said in a statement before a campaign visit to Glasgow.
"But for far too many people and families in Scotland it doesn't feel that way."
He said an independent Scotland would be able to protect the state-funded National Health Service, from what he described as the impact of Westminster cuts, and it would have the job-creating powers of independence to build a more secure economy.
(Reporting by Paul Sandle; Editing by Angus MacSwan)