A pensioner threw ink into the face of best-selling Scottish author Val McDermid after holding a 28-year vendetta over a paragraph in one of her books.

Sandra Botham told the Wire in the Blood writer: “I will see you in hell” and branded her a “fat liar” at a magistrates’ court hearing into the attack.

Botham, who stormed out of the trial, was convicted in her absence of common assault on the author during a Sunderland University book signing.

The 64-year-old, of Ridley Terrace, Hendon, Sunderland, had objected to a paragraph written by Ms McDermid in her 1985 book A Suitable Job for a Woman, which Botham claims was critical of herself and her family.

In revenge, she dressed in disguise, pulling on a blonde wig and hat and, on December 6 last year, threw ink into Ms McDermid’s mouth during the signing session.

At Sunderland Magistrates’ Court, Botham, representing herself, told the bench to “get stuffed” when they refused to allow her to read paragraphs from the book.

She then launched a string of obscenities against the shocked writer who was in the witness box.

Ms McDermid, 58, told the court: “I was giving a public lecture at the university, talking a little about how I became a crime writer and also promoting my latest novel Vanishing Point. I had noticed a woman sitting on the end of one row.

“She caught my eye a few times during the lecture because she appeared to be in disguise, wearing a blonde wig and glasses.

“After the lecture, I was giving a book signing and noticed she was at the end of the queue.

“When she got to the front, she produced a dog-eared copy of A Suitable Job for a Woman which was a non-fiction book I wrote dealing with private eyes in the UK and USA.

“She asked me to dedicate it to “Michelin Man San” and I did, even though I had no idea what that was a reference to.

“She then produced a book that looked like an old Top of the Pops annual and opened it at a page with a picture of Jimmy Savile on it.

“She asked me to sign that too. She was quite insistent. I wasn’t keen, but I get asked to sign all sorts of things so thought it would be easier just to do it.”

It was then Botham pulled a container of ink from her pocket, throwing it across the author, ruining her clothes.

Ms McDermid added: “She then said to me something like ‘you are my female equivalent of Jimmy Savile’ before walking off, out the building.”

Ms McDermid told the court that never in her 25 years as an author had she experienced “anything like this before”.

She added: “I have been told that she took offence to a chapter in the book she asked me to sign.”

The paragraph in the book makes reference to a woman called Sandra who was shaped “like a Michelin Man”.

Cross-examining the author, Ms Botham stood up and said: “Hello Val, we meet again.

“The whole basis of this case depends on what this author has written about me and my family.”

But when told to direct questions at Ms McDermid rather than just reading from her books, Botham told magistrates she was “closing the case” and instead would take it “to the highest court in the land”.

Warned by chairman of the Bench John Bolam that she was doing herself “no favours”, Botham attempted to confront Ms McDermid, before shouting “I’ll see you in hell” and storming out.

Ms McDermid, who comes from Kirkcaldy, Fife, was later escorted to her car by a police officer while proceedings continued in Botham’s absence.

Magistrates found her guilty of the common assault charge and adjourned the case for sentencing.

After the court case, Ms McDermid, who lives in Northumberland, tweeted: "After a day of experiencing the wheels of justice turning very bizarrely, am going to walk by the sea with the dogs."