Mr Cameron will announce his government’s response to the Smith Commission on devolution, with draft legislation which he will say delivers on “the vow” of more powers made to Scotland ahead of last September’s No vote.
In his first major intervention on Scotland’s constitution since the morning after the referendum vote, Mr Cameron will declare in a speech in Edinburgh that Scots have the “best of both worlds”.
Mr Cameron will say: “When the people of Scotland voted to remain part of the United Kingdom, it wasn’t just about the future of devolution, it was because they valued the safety and security of being part of something bigger – our family of nations.
“A strong, stable single currency delivering lower costs for families and businesses. A shared army, air force and navy keeping us safe in an increasingly dangerous world.
“A large domestic market providing more job and investment opportunities. A resilient social union, sharing the costs of pensions and support for those who have fallen on hard times across our nations.
“All within a healthy, strong economy – one of the fastest-growing economies in the developed world.”
The UK government today unveils its draft legislation with clauses explaining how the recommendations of the commission chaired by Lord Smith of Kelvin – and agreed by the Conservatives, Labour, Liberal Democrats, SNP and Greens – will be implemented.
The paper will come under intense scrutiny from the SNP and Yes campaigners for signs that the UK government is failing to deliver on the Smith proposals.
Mr Cameron will say he and other pro-UK parties defied the doubters and managed to bring about the legislation for significant powers ahead of schedule.
He is set to say: “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 timetable.
“We said a command paper would be ready by the end of October – and it was. We said we’d get cross-party agreement by St Andrew’s Day – and we did. We said draft legislation would be published by Burns Night – and here we are, three days before celebrations start, with those clauses before us.
“And now, here we have it: new powers for Scotland, built to last, securing our united future.”
He will also confirm his view that the new powers, including the devolution of income tax, are “guaranteed” whoever wins the election in May.
He will say: “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 and police stations and the responsibility of determining how around 60 per cent of public money in Scotland is spent because – for the first time – the majority of the money the Scottish Parliament spends will be raised right here in Scotland.”
He will point out that this also includes control over £2.5 billion of welfare spending.
Scottish Secretary Alistair Carmichael said that there will be “no surprises” and that the entirety of the Smith proposals will be in the document, “nothing more, nothing less”.
But the Deputy First Minister John Swinney issued a warning. He said: “The proposals which Mr Cameron publishes today must live up to the word and spirit of the Smith Commission. Scotland should not – and will not – accept anything less.
“While the Smith recommendations did not go as far as we wanted and do not live up to the ‘vow’ made before the independence referendum, we welcome them, and they must now be delivered in full.”
Former Scottish Labour leader Iain Gray, who was a member of the Smith Commission, said: “Any politician not excited by the potential these powers will give us to change Scotland for the better should ask themselves if they are in the right job.
“What Scots now need from politicians isn’t another argument over what powers we have. Instead they need to hear how these massive new powers will be used to make Scotland the fairest nation on earth.”