The Big Question: What would happen if Scotland achieved its independence?

Why are we asking this question now?

Today is the 300th anniversary of the signing of the Act of Union between England and Scotland, and if the latest political opinion polls are to be believed it may be one of the last. In little over four months the Scottish parliamentary elections could see the Scottish National Party (SNP) win power, or at least enough votes to hold the balance of influence and push a referendum on independence. And according to recent polls, around 52 per cent of Scots would back moves to dissolve the Union of 1707, which means that after three centuries of shared blood, toil and tears, the marriage of convenience that turned a small island into a world power is shaping up for divorce.

What was the Act of Union?

The treaty of Union signified the end of England and Scotland as separate states and the birth of Great Britain. It was a marriage of convenience. Although the two countries had shared a monarch for almost 100 years since the Union of the Crowns in 1603, when King James VI of Scotland succeeded Queen Elizabeth I, they remained two distinct countries. However, when England found itself at war with France at the turn of the 18th century and King Louis XIV began pushing for the Catholic James VIII to be the rightful heir in both England and Scotland, there was a need to protect the Protestant succession of Queen Anne.

Fearful that Scottish Jacobites would let England's enemies "in the back door" the Westminster parliament threatened to stop all trade with Scotland and deprive Scots of any lands they owned south of the border, unless they agreed to the House of Hanover succession.

In return for creating a new joint country, the Scots were guaranteed access to England's overseas trade routes and the independence of its own legal system, universities and church. After much debate and despite widespread public hostility, both the Scottish and English parliaments were dissolved on May 1, 1707 and replaced with a new British one.

Would a separate Scotland flourish?

If countries such as Malta, with a population less than Edinburgh's, can be self-governing, supporters of independence believe there is no reason why Scotland shouldn't. Optimistic nationalists claim Scotland could be as prosperous as Ireland, Norway, Denmark or Iceland with enough revenue from oil, gas, renewable energy and other industries to invest in a fund to look after future generations. The idea would be to invest revenues in a permanent reserve fund and use the interest to fund public services, pensions and other expenditure for years to come.

According to UK government estimates only about half of the reserves of oil in the North Sea have been extracted so far, which means that there is still enough to support a population of just five million people.

An international convention has determined that the North Sea north of the 55th parallel is under Scottish jurisdiction, which means some 90 per cent of the UK's oil and gas reserves are within Scottish waters.

As far back as 1975, experts recognised that oil could make an independent Scotland one of the richest countries in Europe. A government report saying as much was labelled incendiary, classified as secret and hidden away for 30 years until it came to light at the end of 2005 as a result of Freedom of Information legislation.

In addition to oil Scotland has as much as 25 per cent of the EU tidal and wind resources, which if managed properly could deliver a second energy windfall for the country. However, like any divorce, it is likely that there would be a great deal of argument over the splitting of assets.

Pessimistic supporters of the Union claim that there wouldn't be enough money to finance Scotland's dreams.

Far from being rich, they claim Scotland would have a huge deficit of between £6bn and £11bn and would need to raise taxes which, unionists claim, would drive away much-needed businesses.

What would happen to the relationship between Scotland and England?

If you believe the nationalists, the relationship would change very little and perhaps even improve. For years pro-unionists have argued Scots could not survive without English financial support and as a result many English people perceive Scots as a nation of sponging whingers. Independence would force Scots to stop blaming the English for all their ills and put a stop to southern resentment at "carrying" Scotland. According to pro-unionists Scotland receives far more in subsidy than it contributes to UK coffers. However, separatists argue that Scotland actually subsidises England to the tune of almost £3bn a year.

Culturally, there would be little change as the Queen would remain as monarch, just as she does in other members of the Commonwealth, while Scotland has always had its own legal, educational and religious institutions.

How would Scotland fare in the EU and on the world stage?

As a member state of the European Union, Scotland would possibly have more of a role in international affairs than now, as its politicians could argue their own case. Unionists have warned that an independent Scotland might not be able to join the EU if the UK was split. However, such a situation is highly unlikely, not least because the same argument of denying membership could be applied to an independent England. Similarly, many countries share overseas embassies and assets and there is no reason why Scotland and England couldn't continue to co-operate.

Would it be secure?

The SNP has already said it would scrap Trident, the nuclear submarine deterrent, and would prevent Scottish troops from taking part in any future illegal wars - such as the invasion of Iraq. This, they claim, would likely make Scotland less of a terrorist target. However, Scotland would continue to have a conventional military defence that would work alongside English forces in the mutual defence of the British Isles.

What would happen to the rest of the UK?

With a population more than 10 times the size of its northern neighbour England will always be the dominant force in the British Isles but without Scots troops and revenue, it would probably have to adjust to a diminished role on the world stage. And while England would retain Britain's nuclear deterrent, it would mean having to find a new base for the Trident fleet and supporting it from a smaller national defence budget.It is also possible that if Scotland made a success of independence, this would hasten calls for Wales and Northern Ireland to seek self-determination of their own.

Could Scotland survive as an independent nation?

Yes...

* Scotland would be much wealthier and better prepared than many other independent nations around the world

* Revenue from oil and other energy industries could be invested to provide a secure fund to support future generations

* Much of the political and civil infrastructure needed to administer the country is already in place, and the people are highly educated

No...

* Without subsidy from the rest of the UK, it is claimed by unionists that there would be a fiscal deficit of up to £11bn

* Nationalist promises to cut taxes while increasing spending on pensions and higher education would put the country in the red

* If the bonds that unite Britain were severed, all the countries of the union would suffer economically and culturally