millionaire author JK ­Rowling, who adopted Scotland as her home, has explained why she wants it to remain part of the UK after donating £1 million to the campaign against independence.

The Harry Potter author, who lives in Edinburgh, has highlighted her concerns about the economy and medical research.

Her donation is by far the biggest yet for the pro-Union campaign, while Yes Scotland has benefited from £2.5m from Colin and Chris Weir, who won £161m in the EuroMillions lottery in 2011.

Ms Rowling said that while she was "no fan of the current Westminster Government", she had concerns about the economic risks of independence.

"Scotland has punched above its weight in just about every field of endeavour you care to mention, pouring out world-class scientists, statesmen, economists, philanthropists, sportsmen, writers, musicians and, indeed,Westminster Prime Ministers, in quantities you would expect from a far larger country," she said on her website.

"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 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'.

"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 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."

But she added: "If the majority of people in Scotland want independence I truly hope it is a resounding success. While a few of our fiercer nationalists might like to drive me forcibly over the Border after reading this, I'd prefer to stay and contribute to a country that has given me more than I can easily express."

Ms Rowling also said all the major parties are "wooing" voters with the offers of extra powers. She argued this was to keep the country "happy so it does not hold an independence referendum every 10 years and cause uncertainty and turmoil all over again."

She added: "I doubt whether we will ever have been more popular, or in a better position to dictate terms, than if we vote to stay."

Her donation to Better Together and her article sparked an outpouring of internet abuse, some of it of questionable providence.

However, her words also generated the sort of better, kinder and more informed debate for which many are calling.

Mairi McFadyen, a research assistant at Edinburgh University, writing for the pro-independence artists' body National Collective, said: "To be asked, 'What kind of country do you want to live in?' is the most wonderful gift."

"Neither do I share your confidence about devolution post-No. Devolution has protected us from what is being done to public services south of the Border.

"The only possible means to protect what is vital is to vote Yes."