JK Rowling, the author of the Harry Potter books who lives in Scotland, gave £1 million to the campaign to keep the country in the UK ahead of a referendum on independence.

The Better Together group confirmed the size of the donation, which Rowling said in a letter on her website was “substantial” after weighing the arguments before the September 18th vote.

As a Scottish resident, Rowling gets to cast a ballot. “My hesitance at embracing independence has nothing to do with lack of belief in Scotland’s remarkable people or its achievements,” she said. “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 nationalist and pro-UK campaigns failed to gain any ground on each other last month, according to a survey published today. Pollster TNS said 42 per cent of respondents plan to vote to remain in the UK, with 30 per cent supporting independence and 28 percent undecided.

The 12 percentage-point gap was unchanged from the month before. Scottish National Party leader Alex Salmond said in an interview in Aberdeen that Rowling is "entitled to express her views, just like everybody else."

The campaigns have entered a period when their spending is regulated, he said. Prime minister David Cameron "encourages and welcomes support for the case for the UK staying together from across all quarters," his spokesman, Jean-Christophe Gray, said.

Bloomberg