Harry Potter author J K Rowling yesterday continued her promotional tour amid tight security - but laughed off suggestions that she is being stalked.

The millionaire writer is travelling across Britain by steam train as part of a whistle-stop book-signing tour to promote her fourth book in the series, Harry Potter and the Goblet of Fire, which has begun shattering publishing records since its release at midnight on Friday.

Her success has led to reports about obsessive fans, including one male admirer who has reputedly showered her with love letters and was spotted standing outside her home.

But the 34-year-old writer said yesterday that reports of a stalker were news to her.

'It's just wishful thinking. I haven't got a clue about it and that's the truth. I would like them to tell me if there was anything,' she said during a visit to York.

Ms Rowling was accompanied by two female bodyguards during the visit.

One stayed close to the author's side, while the other scanned the waiting crowds.

Other security personnel, wearing black suits and earpieces, were also in attendance.

A spokesman in charge of security said: 'We are just making sure everybody is all right. There's a lot of children here and we want to ensure everybody is safe and gets their books signed.'

The author, a single mother with an eight-year-old daughter, looked tired and anxious during her visit to the National Railway Museum in York, where 400 children gathered for a signing.

She said: 'It's been very, very busy. I was half-expecting it and was braced for it but it's still taken me by surprise.'

Wearing a black patterned cardigan, black trousers and boots, she said her success had come as 'a bit of a shock'.

The promotional tour set off from London yesterday and will arrive in Perth on Tuesday, following stops in Bristol, Didcot, Kidderminster, Manchester, York, Newcastle and Edinburgh.

The first British and US print run of 3.3 million copies of the new Harry Potter book has taken £5 million in advance orders alone and several bookshops have reportedly sold out of copies.

Daniel Rippon, aged ten, of Heworth, York, was very excited to be meeting the author.

'I was really, really happy when I found out. Harry Potter books are brilliant, with lots of cliff-hangers at the end of each chapter,' he said.

Harry Potter has mysteriously failed to materialise on the list of the five books borrowed most often from primary school libraries, according to a new survey.

The apprentice wizard, whose latest exploits have been breaking publishing records, did not even appear in the top 20 most popular school library titles for young children, according to the Schoolsnet.com poll.

Old children's favourite Roald Dahl is still a winner, with two titles in the top 20, Charlie and the Chocolate Factory and The Twits.

Mr Greg Hadfield, Schoolsnet's chairman, said: 'With its mix of old and new titles, well-established and lesser known authors, the results reflect children's wide-ranging imagination and reading habits.'

The top five most borrowed books were:

• Twinkle, Twinkle Chocolate Bar by John Foster
• The Truth About Guy Fawkes? by Terry Deary
• Flight - Fliers And Flying Machines by David Jefferis
• There's An Alligator Under My Bed by Mercer Mayer
• Timelines - Ships And The Sea by Richard Humble

The survey tracked more than 100,000 borrowings at 40 primary schools.