AUTHOR JK Rowling has threatened to sue former SNP MP Natalie McGarry for defamation after the politician accused the Harry Potter author of defending “abusive misogynistic trolls”.

McGarry’s accusation came on Thursday night when she tweeted: “Wow @jk_rowling vanity searches her name & then defends abusive misogynist trolls. Extraordinary. Almost makes me regret queueing for books.”Rowling responded to say she would “love an explanation” for McGarry’s comments.

The MP’s claims centre around an anonymous Twitter account in the name of Brian Spanner. The account regularly posts badly Photoshopped pictures and expletive-filled comments about the SNP and pro-independence supporters. It has in the past tweeted extremely abusive comments about female politicians.

Spanner is one of the 280 accounts Rowling follows on Twitter and the two often talk on the platform.

The argument lasted around six hours, with Rowling demanding McGarry prove her claim. At one point McGarry tweeted: “On reflection, I shouldn’t have accused Joanne Rowling of anything based on folk she tweets or retweets, and sends supportive tweets to.”

However, she then went on to post what she claimed were screengrabs of Rowling defending Spanner, calling him a “good man” after a particularly insulting tweet about Alex Salmond. Unfortunately for McGarry they were three separate tweets that had been Photoshopped together. Rowling had said “good man” to Spanner after he donated money to her charity Lumos.

Alan Ferrier, the man who posted the screengrab, said it was not meant to be misleading.

He apologised yesterday morning: “Following a night’s reflection, it’s clear that my tweet was misleading, crudely presented and ill-advised. In retrospect, I should have left dates on the tweets to make it clear that I was not describing a conversation. I have made donations to both @jk_rowling’s charity Lumos and to @WomenForIndy and will be taking a break from Twitter for a while to regain some much-needed perspective.”

The threat of legal action came as Rowling tweeted McGarry: “You don’t appear to understand how Twitter or defamation works. I’m going to help you out with the latter.”

Rowling was a prominent supporter of the Better Together campaign during the referendum.

McGarry, the MP for Glasgow East, withdrew from the SNP whip last November over allegations around money, understood to be between £30,000 and £40,000, missing from the accounts of Women For Independence campaign. Both McGarry and Rowling declined to comment.