It’s 19 September 2014. The Scottish people have voted for independence. Does David Cameron resign? Would sterling be legal tender in Scotland? Would you need a passport at Gretna Green? Guardian specialists answer the key questions thrown up by the ending of the union

Would Scotland be in the EU?

Yes. Almost certainly. But it will not be as easy or as quick as Scotland’s first minister Alex Salmond and the yes camp say. The issue sits astride a legal conundrum. There is no provision in the EU treaties for a member state of the EU falling apart, with the breakaway part then joining the EU. Legal problems abound. Scotland will probably have to apply to join, says Brussels. That needs the agreement of the other 28. There will be humming and hawing in Spain, Belgium and other countries facing separatist challenges.

But in the end politics will trump legal niceties. It will be very difficult for Brussels to ignore a free, peaceful, democratic referendum outcome without looking anti-democratic. Besides, the entire body of EU law and regulation already applies in Scotland, so negotiations should be relatively smooth.

But there will be arguments over the UK rebate from the EU budget and over the euro single currency (all new members have to commit to join it). Membership needs to be ratified by the other 28 parliaments and the European parliament. Salmond claims it can all be done in 18 months. That looks like wishful thinking. Ian Traynor

Would Scotland keep the pound?

Facebook Twitter Pinterest Three banks – Bank of Scotland, Clydesdale Bank and RBS – are still allowed to issue their own notes. They are legal currency but not legal tender. Photograph: Murdo MacLeod for the Guardian

Salmond insists the country will continue to use the pound if it votes for independence. But all three main political parties at Westminster say they would block such a currency union. Currency experts see four main possibilities after a yes vote: keep sterling as part of a formal currency union; use the pound, but not in a formal currency union (known as “sterlingisation”); join the euro; or create a new currency. On the first option the Scottish National party says Westminster parties are bluffing when they insist that such a deal would be impossible – something they of course deny. The euro option would take time, if it was at all possible. Sterlingisation means not having a lender of last resort to guard against financial shocks. Creating a new currency would be costly but offers more control over monetary policy. It’s all but impossible to say which will actually happen.

Katie Allen

Would David Cameron resign?

Facebook Twitter Pinterest David Cameron has said he would not resign if Scotland votes for independence. Photograph: Murdo MacLeod for the Guardian

He says no, and there is no legal or constitutional issue with him continuing at the helm of a country which, under his watch, has just lost a third of its landmass and approaching a 10th of its people. But he would unarguably be a diminished leader of a diminished country, and his many critics on the Tory benches would seize every chance to point out that their movement remains, technically speaking, still the “Conservative and Unionist party”. So he would be under great pressure. His ability to withstand it might depend on whether or not a dejected Labour party was panicked into giving Ed Miliband the boot: all politics is relative, so one leader’s loss could be another leader’s gain. There may be no obligation to quit, but with both parties facing simultaneous crises, it might be a question of which side’s was worse. It’s hard to imagine both surviving.

Would Labour ever form a Westminster government again?

Facebook Twitter Pinterest Ed Balls with a Labour voter in Aberdeen. Photograph: Murdo MacLeod for the Guardian

For the best part of 20 years, it has been possible to count Scottish Tory MPs on one finger – or none. Labour, by contrast, claims 41 of the nation’s 59 seats, and their ejection would close off all of Ed Miliband’s easiest routes to Downing Street. It does not, however, make winning impossible – instead of requiring 68 gains for a majority today, without Scotland Labour would require 80 gains.

That is more gains in a smaller House of Commons, of course, but with a fair wind it could be done. Tony Blair’s big wins were all wins without Scotland, as – looking further back to a time when Scotland was less different – were the big wins of Attlee and Wilson. But in the tight elections of 1964, 1974 and 2010 excluding Scotland would have materially tilted the balance to the right. With few expecting a Labour landslide this time, a yes win would invite Labour cries of “oh no”. Tom Clark

Would Scotland keep the BBC?

Facebook Twitter Pinterest BBC Pacific Quay is BBC Scotland’s television and radio studio complex in Glasgow. Photograph: Murdo MacLeod for the Guardian

An independent Scotland would surely have access to BBC services – as many other countries around the world do. But on what basis? Westminster won’t publish its view before 18 September; the BBC can’t. The Scottish government proposes a reciprocal deal, whereby its new national broadcaster, the Scottish Broadcasting Service (SBS), would take on BBC Scotland’s current resources and the £320m in licence fees from Scottish viewers to match current output from north of the border, in return for ongoing free access to the rest of the BBC’s output.

But the Scottish government’s figures – £320m in licence fees from Scotland v £175m spent in Scotland – are somewhat misleading. Viewers do not currently reap only the benefits of BBC cash spent within Scotland’s borders. And would SBS programmes be a fair swap for free access to all the BBC’s TV, radio, online and digital services such as iPlayer? Licence-fee payers in rUK (the rest of the UK) might not see this as good value for (their) money.

The BBC would surely want to make a deal in the event of a yes vote: it’s likely that deal would be a commercial one, under which Scottish viewers pay no more for a licence fee but the government, via SBS, pays for BBC programming. It is what works in Ireland. Chances are, though, it will cost more than the Scottish government would have voters think. Claire Phipps

Would I need a passport to cross the Scottish border?

Facebook Twitter Pinterest A Scottish passport holder and purse. Photograph: Jeff J Mitchell/Getty Images

A deal to keep an independent Scotland within the common travel area – as the Scottish government proposes, and as Ireland already is – looks to be the most straightforward and workable solution. But political rows over immigration could be a real obstacle. It is hard to see a Westminster government of whatever hue signing up to an open border agreement with an independent Scotland that is taking a markedly different tack on immigrants. (The first minister, Alex Salmond, has said he wants to see net migration rise to about 24,000 a year.)

The issue of EU membership makes this yet more twisty. Should Salmond be wrong about the smooth transition to full EU membership, the Schengen problem could become very real. Given current attitudes to the EU and immigration within the wider UK, it is not hard to assume that if Scotland has to sign up to free movement for all EU nationals, the rest of the UK would be even more inclined to shut the door. Until there is a clearer answer on Scotland’s future membership of the EU, the passport issue is likely to remain unresolved. CP

What would happen to Trident?

Facebook Twitter Pinterest Faslane submarine base, home of Trident. Photograph: Murdo MacLeod for the Guardian

Scotland would have one of the smallest budgets of any Nato member (should it be allowed to join). But perhaps that would be in keeping with the kind of global player an independent Scotland would wish to be.

The SNP wants to see the removal of nuclear weapons – that is, Trident, the four submarines, plus missiles and warheads that make up the UK’s nuclear deterrent – from Scotland within the first term of parliament following independence. The Westminster government says the costs of moving it, along with the headache of finding another suitable location, make this an unrealistic, even dangerous, proposition.

In the midst of wider uncertainty about the future of the nuclear deterrent more generally, Trident could prove to be an important bargaining chip. In the event of a yes vote, the impracticalities of housing the weapons in a country that does not want them, as well as public opinion in rUK (the recent British Social Attitudes survey, published in June, found that only 26% of those in England and Wales thought Trident should stay in Scotland post-independence), could well force Westminster to undertake the momentous process of shifting the base, its submarines and warheads despite its reluctance. CP

Would Scotland keep its oil revenues?

Facebook Twitter Pinterest The Grangemouth oil refinery. Photograph: Murdo MacLeod for the Guardian

The North Sea has always been seen as crucial, not only to employment and tax revenues, but to the whole viability of Scotland as a thriving and independent nation state. It is assumed on both sides of the border that 91% of those tax revenues could be taken by Scotland on the basis of an internationally accepted median line drawn out between Scotland and England straight out into the sea.

Salmond, a former oil economist, has argued that a newly independent country could exploit the £54bn in tax taken from the North Sea in the six years up to 2016-17. And he believes that there are 24bn barrels of oil equivalents (boe) of reserves – which includes gas – still lying under the seabed and waiting to be exploited.

Such figures have proved a major bone of contention. The Office for Budget Responsibility has predicted recoverable reserves of 10bn boe and North Sea tax revenues of just £61.6bn between now and 2040. Terry Macalister

Would the Queen remain Queen of Scotland?

Facebook Twitter Pinterest The Queen and the Prince of Wales watching the action during the Braemar Highland Games. Photograph: Chris Jackson/Getty Images

Yes, in the short term at least. An independent Scotland would begin with a draft constitution that would change little and would leave the Queen in place, says Adam Tomkins, professor of constitutional law at Glasgow University. A yes vote would not imply Scotland should become a republic because the referendum concerns the 1707 union of the nations and not the union of the crowns, which happened in 1603, when James VI of Scotland became James I of England. A widespread public consultation on a permanent constitution would follow a yes vote and Scotland’s justice minister, Kenny MacAskill, has said of the monarchy: “It will be for the people of Scotland to decide.” That means it could come down to another referendum. Robert Booth

Would the 2015 general election be cancelled?



Facebook Twitter Pinterest A polling station. Photograph: Jon Super/AP

There has been excited talk on the Tory benches of answering a yes vote with a delay in the general election from May 2015, the argument being that it would be wrong for Scotland to have a say in choosing the government of a union it had chosen to leave. It would indeed be awkward in the extreme if Scottish Labour MPs put Ed Miliband into Downing Street immediately before disappearing, but it is less likely than it looks on paper (after a yes vote, the party would lose many Scottish members: how many Scottish Labour incumbents would even stand?). More fundamentally, with the blitzkrieged exception of 1940, parliamentary terms are never extended. The Parliament Act of 1911 expressly precludes the Commons from fiddling with election dates without consulting the Lords. And, particularly from a government that so recently legislated to fix the election date for the first time, the argument simply wouldn’t wash. TC

Would Scottish MPs have to leave Westminster?

Yes, without doubt, the MPs would have to go in the end: their exit is central to what independence means. After all, Sinn Féin still refuses to take its Westminster seats from Northern Ireland, just as Sinn Féin members from Ireland as a whole refused to sit in an alien parliament before 1922. After a yes, Scottish MPs would be elected along with everyone else next May, and then leave the House along with everyone else on May 2015. Then, under Alex Salmond’s plans, independence day follows in March 2016, at which point they leave the House because their seats cease to exist. While a referendum yes would surely achieve independence in the end, the timetable is perhaps not quite as certain. All sorts of legislation would be required, and if the accompanying negotiations went badly, might things get delayed? If so, the Scottish MPs could be around for a little longer. TC

What would happen to our P5 seat at the security council?

Facebook Twitter Pinterest United Nations building in New York. Photograph: Doug Armand/Getty Images

The Foreign Office line is that in the event of Scottish independence the rest of the UK would retain its permanent place on the United Nations security council. That seat is prized by the Foreign Office. Britain is only one of five permanent members of the council – along with Russia, the US, France and China – and, like the other four, has a veto.

A Foreign Office spokesman has said “independent legal opinion sought and published by the UK government” had clarified that the UK would continue on existing terms and Scotland would be an entirely new state. But there is one huge caveat to this: UK membership of the security council is dependent on Scotland not declaring that both countries are new states. If Alex Salmond wants a bargaining chip over currency or anything else, he has a big one.

There are lots of states such as India and Brazil that want to be permanent members that would take the opportunity to end Britain’s prized status. There are also members of the European Union that think the UK should give up its seat anyway and make it an EU one. Ewen MacAskill

How would big companies headquartered in Scotland but listed in London react?

Facebook Twitter Pinterest Royal Bank of Scotland headquarters at Gogarburn, Edinburgh. Photograph: Murdo MacLeod for the Guardian

Neither Royal Bank of Scotland nor Lloyds Banking Group – owner of Bank of Scotland – have said so in public but the expectation is that both bailed-out banks would move their main bases from Scotland to London in the event of a yes vote. The business secretary, Vince Cable, said as long ago as February that it was inevitable that the 81% taxpayer-owned RBS would move south. The expectation has been fuelled by the fact that the two big banks have assets that are 12 times that of the Scottish economy.

The Edinburgh-based insurer Standard Life has announced it has set up a number of English subsidiaries as part of a contingency plan in the event of a yes vote, although other major Scottish companies such as Aberdeen Asset Management have not taken such precautions.

Independence would officially take place in March 2016, which would give companies 18 months to make any switch or make a decision about adapting to stay in Scotland. Jill Treanor

How would Scotland and the United Kingdom fare in sports after the referendum?

Facebook Twitter Pinterest Sir Chris Hoy with his London 2012 gold medal for the keirin. Photograph: Rex Features

In team sports, independence would bring little change. Gordon Strachan’s football team will continue to strive to qualify for their first major tournament since 1998 and the rugby union side would continue their preparations towards next year’s Rugby World Cup.

It is in Olympic sport where the most upheaval would be felt. Scottish athletes contributed to 13 of Team GB’S triumphant haul of 65 medals at the London Olympics amid a flood of rhetoric about the togetherness of the British team.

Despite only making up just over 10% of the number of athletes funded through the £125m-a-year high-performance scheme administered by UK Sport, Scottish athletes won 20% of the overall British total. At the Sochi Winter Olympics earlier this year, the total was 50% thanks to the success of the all-Scottish curling teams.

Some fear that devolution could undermine the success of the sporting system built since 1996 via an influx of lottery money and the creation of a string of national centres of excellence. Likely rows over how lottery money should be divided and whether Scotland could be admitted into the International Olympic Committee in time to take part in the 2016 Rio Games also loom in the event of a yes vote.

But advocates of independence believe sport could be a powerful tool in forging a new identity for Scotland and believe it would continue to punch above its weight on the international stage, producing successors to Sir Chris Hoy and Katherine Grainger.

Meanwhile, with Andy Murray representing Scotland, the search for the first Englishman to win the Wimbledon singles since 1936 may become a new annual obsession. Owen Gibson