The British government began a historic transfer of powers to Scotland on Thursday (January 22), keeping a pledge it had given to persuade Scots to reject independence as renewed nationalist support surges.

The draft bill, to be enacted after a general election on May 7, will further dismantle Britain's highly centralised system of government, a move critics fear could trigger the beginning of the end of the United Kingdom.

It has already spurred demands from some politicians for similar moves in England, Wales and Northern Ireland, teeing up political uncertainty and heralding an eventual redistribution of power in the world's sixth largest economy.

Under the law, Scotland, which voted to reject full independence in a referendum in September, will be able to set income tax rates, have some influence over welfare spending, and be given the authority to decide how the Scottish parliament and other structures are elected and run.

"Because in September, the people of Scotland came out in record numbers to decide the future of the United Kingdom. They voted clearly and decisively to keep our family of nations together. But a no vote didn't mean no to change. The leaders of the other main political parties and I promised extensive new powers for the Scottish parliament - a vow with a clear process and a clear timetable," British Prime Minister David Cameron said in a speech in the Scottish capital Edinburgh.

Cameron and the other main parties had promised draft legislation by Burns' night, January 25, and Cameron said they had stuck to their promise as he held up the document.

"We said that draft legislation would be published by Burns' Night and here we are, three days before the celebrations start, with those draft clauses before us, set out very clearly in 47 pages of this document," he said.

Cameron, whose party is deeply unpopular in Scotland, moved to quell nationalist doubts the draft law would reach the statute book.

"Be in no doubt - whoever forms the UK government after May 7th, these new powers are guaranteed," said Cameron.

"The Scottish parliament will have more control of its tax and spending, making it one of the most powerful devolved parliaments in the world. The Scottish parliament will combine the freedom to decide what happens in Scotland's schools, hospitals, surgeries, police stations, with the responsibility of determining how around 60 percent of public money in Scotland is spent. Because for the first time, the majority of money the Scottish parliament spends will be raised right here in Scotland," he continued to say.

The pro-independence Scottish National Party (SNP) welcomed the law's publication but complained it did not go far enough and left the British government with too much power in Scotland.