AN independent Scotland would overcome a "challenging" economic inheritance with an ambitious programme to increase immigration, cut taxes and provide full-time child care, Alex Salmond has pledged.

The First Minister yesterday unveiled the SNP's plans for the first years of an independent Scotland as he published the Scottish Government's long-awaited blueprint for how the country would operate.

Launching the 670-page White Paper on independence, Scotland's Future, at Glasgow Science Centre, he said it was a "mission statement" for leaving the UK on March 24, 2016.

Alistair Darling, the head of the pro-UK Better Together campaign, dismissed it as a "work of fiction, full of meaningless assertions" that left key questions unanswered.

The White Paper - which, in its online version, registered 50,000 hits by 5.30pm yesterday - restated the Yes campaign's central claim that decisions about Scotland should be taken by those who live in the country.

But, for the first time, it presented the SNP's detailed manifesto for how an independent Scotland would be run if they held the reins of power after the 2016 Holyrood election.

The document came a week after the Institute for Fiscal Studies warned an independent Scotland would face a tougher challenge to bring its debts under control than the rest of the UK over the coming 50 years because of its rapidly ageing population and the decline of North Sea oil revenues.

Yesterday Mr Salmond said control over immigration would be a "major gain" of independence and a key tool to grow the economy.

The White Paper did not set a target for new immigrants but, in order to rebalance Scotland's ageing population, outlined an Australian-style points system to attract people with skills needed for the economy.

Financial and salary thresholds for immigrants would also be cut to encourage more people to settle in Scotland, and work visas, or green cards, for overseas students would be introduced.

To help bring more women into the workplace, the SNP pledged a £600 million per year scheme to provide near full-time free child care for children aged one to four by 2024.

The plan would be achieved in stages, the White Paper said, with all three and four year olds entitled to more than 1000 hours per year - equivalent to primary school hours - in nursery classes by 2020.

Also on the economy, the SNP pledged to set a timetable for cutting corporation tax by 3p in the £1 in a move they claim would create 27,000 jobs over 20 years.

Air passenger duty, paid by travellers, would be cut by 50% by 2020 and eventually abolished, in a bid to boost tourism. The SNP also promised to "begin the process" of renationalising Royal Mail.

Mr Salmond said his plans amounted to "nothing less than a revolution in employment and social policy for Scotland, with a transformational change in childcare at the heart of those plans".

Opponents, however, insisted key questions remained.

Mr Darling said Scots were still in the dark about the currency of an independent Scotland after the White Paper repeated the SNP's proposal to keep the pound in a currency union with the UK - a plan the UK Government says it is unlikely to accept.

In another potential area of uncertainty, it emerged that access to the full range of BBC programmes and services would depend on a newly created Scottish Broadcasting Service, based on BBC Scotland, becoming a "joint venture" with the UK-wide BBC.

The White Paper also acknowledged that Scots might lose their British citizenship if the UK refused to extend dual nationality rights.

The White Paper said the Scottish Government expected Scots to retain UK citizenship but added: "It will be for the rest of the UK to decide whether it allows dual UK/Scottish citizenship."

The White Paper repeated previous pledges to maintain pensions and uprate the minimum wage in line with inflation.

The SNP said it would ask the UK Government not to roll out its central welfare reform, the Universal Credit, in Scotland in the event of a Yes vote and, as expected, also promised to abolish the so-called bedroom tax.

Among areas which the SNP insists would not change significantly under independence, the White Paper said the National Lottery would continue, while knighthoods and other honours would also remain, subject to amendments agreed with the royal household.

The official name of the newly independent country would be "Scotland", the document noted, in case of doubt.

On Europe, the White Paper argued Scotland could become a full member of the EU "seamlessly", without having to reapply, under Article 48 of the main Brussels treaty, following advice from the Lord Advocate.

Global representation would be provided by 70 to 90 embassies and consulates at a cost of up to £120m per year, less than Scotland's share of Foreign Office spending. Detailed plans for defence, revealed for the first time, included using up to 13 vessels from the Royal Navy and a squadron of 12 Typhoon jets based at Lossiemouth.

Recruitment remained unclear, however, with the possible transfer of personnel to the proposed Scottish Defence Force a matter of negotiations.

Serving Scots would not be under any obligation to switch, the document said, a factor reflected in the anticipated initial strength of the SDF of 9500 personnel, fewer than half of the 20,000 planned long term.

In a pledge that would delight supporters, an independent Scotland would seek to remove Trident nuclear weapons from the Clyde by 2020, the SNP vowed, despite speculation the move could take 20 years.

Elsewhere, athletes will travel to compete at the Rio Olympics under the Scottish flag, the White Paper claims. Scotland would hope to build on success in London, where Sir Chris Hoy and Andy Murray won as part of Team GB.

Mr Salmond said: "This is the most comprehensive blueprint for an independent country ever published, not just for Scotland but for any prospective independent nation.

"We do not seek independence as an end in itself, but rather as a means to changing Scotland for the better.

"Our proposals will make it far easier for parents to balance work and family life, and will allow many more people, especially women, to move into the workforce, fostering economic growth and helping to boost revenues - which will in itself help pay for the policy."