Ever since Scotland's First Minister, Alex Salmond, announced the referendum will take place on September 18, people on all sides have joined the debate.

President Barack Obama, speaking at the G7 summit, said the United States has a deep interest in ensuring the UK remains strong, robust and united - music to the ears of the Better Together campaign.

Wimbledon champion Andy Murray said he didn't like it when Salmond, the Scottish National Party leader who heads the Yes Scotland campaign, unfurled a Scottish flag when the player won the tournament last year.

Mr Salmond suggests politicians on the Yes side for are more popular than their opponents which gives them a credibility advantage.

Former chancellor Alistair Darling, who heads the Better Together campaign, has accused the opposition of running out of arguments and time.

Dr Eamonn Butler, the director of the Adam Smith Institute, said: "I think the No campaign will win. They have been ahead in the polls for some time and even though the polls are narrow and there are a lot of undecideds, the Scots have realised that they have a pretty good deal at the moment. They got a lot of money from England and at the same time they have a Parliament which decides policy in terms of health and education and other things like that."

There are dangers for the No campaign according to Butler who says research indicates that a lot of those who haven't made up their mind would vote yes if it came down it.

He said in the event of a victory the No campaign will be able to demand more concessions from London over the powers exercised in Edinburgh.

Butler also pointed to other issues that may swing the vote in favour of the No camp.

"I think people are very concerned about things like what currency would be usable in Scotland. England says that if Soctland uses the pound they would have no say in monetary policy. There's a very big question about membership of the European Union because many other countries have separatist movements and the last thing they want is to see a separatist movement in Britain winning and then being automatically entered into the European Union."

Dr Eamonn Butler said North Sea Oil, a major revenue earner in Scotland, is declining, and an independent Scotland would have less power in NATO and the EU.

Dr Nicola McEwen, a senior politics lecturer at Edinburgh University, explains the key aspect if the Yes campaign is to win.

"One of the things it has to do is convince women. There is a significant gender gap in all of the opinion polls with women 13 percentage points less likely to support independence than men. If this was a just a vote for men then they would look like they could win it, perhaps not comfortably, but certainly secure a majority."

Dr McEwen says the Yes campaign is trying to promote issues that will be of more interest to women like child care.

She added there's no clear explanation for the gender difference but it may relate to women being more risk averse and uncertain about the consequences of independence.

Dr McEwen said the economy will be the biggest issue in the referendum but the future of the welfare state will also be a significant factor.

"Another issue is around the future of the welfare state and whether people are convinced that independence will secure the welfare state as it currently is but also promote an opportunity to have a more progressive welfare state in the future. That's capitalising a little bit on the current UK government's approach to welfare which is to cut it back, to reduce the size of the state, to pass on some of the deficit burden to groups who are vulnerable and dependent upon benefits."

There will be plenty more arguments between now and September about the pros and cons of Scotland becoming an independent country.