Harry Potter author J.K. Rowling has donated $1.6 million (£1 million) to the campaign against Scottish independence.

In a lengthy statement on her website explaining her backing of the Better Together Campaign, the Edinburgh-based writer says her donation stems from concerns that the push for independence underestimates the risks of breaking away from the United Kingdom in a competitive global market.

She writes, "I came to the question of independence with an open mind and an awareness of the seriousness of what we are being asked to decide... My hesitance at embracing independence has nothing to do with lack of belief in Scotland's remarkable people or its achievements. The simple truth is that Scotland is subject to the same 21st-century pressures as the rest of the world. It must compete in the same global markets, defend itself from the same threats and navigate what still feels like a fragile economic recovery. The more I listen to the yes campaign, the more I worry about its minimisation and even denial of risks.

"Whenever the big issues are raised - our heavy reliance on oil revenue if we become independent, what currency we'll use, whether we'll get back into the Eu - reasonable questions are drowned out by accusations of 'scaremongering.' Meanwhile, dramatically differing figures and predictions are being slapped in front of us by both campaigns, so that it becomes difficult to know what to believe."

She adds a decision to leave the Union could leave Scotland in a weak bartering position with its neighbours, writing, "If we leave, though, there will be no going back. This separation will not be quick and clean: it will take microsurgery to disentangle three centuries of close interdependence, after which we will have to deal with three bitter neighbours. I doubt that an independent Scotland will be able to bank on its ex-partners' fond memories of the old relationship once we've left. The rest of the Uk will have had no say in the biggest change to the Union in centuries, but will suffer the economic consequences."

She closes the missive by writing, "Whatever the outcome of the referendum... it will be a historic moment for Scotland. I just hope with all my heart that we never have cause to look back and feel that we made a historically bad mistake."

Rowling, who is a long-standing supporter of the Labour Party, is now responsible for the biggest single donation to the Better Together Campaign, which is run by her friend and former U.K. Chancellor of the Exchequer Alistair Darling.

Scottish citizens will vote in a referendum on the issue of independence in September (14).