A NEW row over political trolling has erupted as it emerged one of Scotland's most prominent female academics described the new SNP MP Mhairi Black as a "slut".

The derogatory comments came from Jill Stephenson, an historian, prominent unionist and emeritus professor at the University of Edinburgh who goes by the twitter name @Historywoman.

The insults thrown by the historian towards Black, the youngest MP in the House of Commons, prompted the SNP to call for everyone involved in the debate over Scotland's political future to be "respectful at all times".

The Twitter remarks were made before the general election when discussing those who were standing for Parliament for the SNP.

The row over Stephenson's attack on Black comes against a backdrop in which Scottish Labour produced a dossier detailing online abuse from apparent SNP members and independence supporters, and widespread criticism in the unionist press of so-called 'cybernats'.

After one tweeter questioned the calibre of the SNP candidates, Stephenson said: "They aren't even the worst. Have you seen/heard the appalling harridan Mhairi Black? Foul mouthed little slut."

In a separate thread she remarks: "If electors vote for a foul-mouthed slut like M Black, it says a lot about them, and none of it is good."

Before the referendum, Edinburgh-born Stephenson was described by one newspaper as "one of the most compelling voices in support of the Union" as an essayist, letter writer, blogger and a member of the Financial Times' readers' panel.

She is a former acting director of the Center for the Study of Modern Conflict and an expert on Nazi Germany and the history of women. Her publications include Hitler's Home Front: WÃ¼rttemberg under the Nazis and Women in Nazi Germany.

Her abuse has been strongly criticised. One tweeter @LeftPeggers said: "What a dreadful thing to say, on all fronts. Shame on you."

And @HistoryWoman remarked: "Shame on all those who voted for a party that has lied systematically. Simply in order to win votes."

When @Indepshop questioned her judgement, Stephenson, 71, responded: "I don't give a flying f*** about what you think about me or anything else. Sod off."

An SNP spokesman said: "As we have repeatedly stated, the online debate in Scottish politics should be respectful at all times - that clearly includes people who oppose the SNP and independence, as this person demonstrates, and we trust that the other parties will do all they can to root the abuse out."

Stephenson has herself reacted angrily to abuse directed at her. When one tweeter Ian Corrigan (@FreeScotTillDie) told her she was "stupid enough to vote for paedophiles", she responded: " Ah, point seven on the SNP crib sheet. When you run out of any arguments, wave a shroud and shout 'paedophiles'."

Corrigan responded saying: "And people like YOU are why children were abused you vile horrible bitch".

Stephenson said: "Do tell me your evidence for associating me with child abuse? You are in danger of slandering me."

Corrigan replied: "Feel free to consult your solicitor."

The comments came at a time when Mhairi Black was coming under fire over video footage which featured controversial comments in the aftermath of Scots backing the Union in which she spoke about wanting to "put the nut" on victorious "fat cat" Labour councillors at a Hope over Fear rally held in George Square.

Black, 20, who graduated with a first class honours degree in politics from Glasgow University now sits on the Work and Pensions select committee, and featured in Time magazine.

She was up against one of the best-known Labour MPs left in Scotland, then shadow foreign secretary Douglas Alexander, who was defending a majority of more than 16,000 when she romped to victory in the General Election.

Asked to comment on her tweets and the comments directed at her, Stephenson said: "Why don't you print news rather than reheated dross?

"You don't 'have to' ask me anything, and I don't 'have to' respond. If I thought my comments would be relayed faithfully, I might think about it. But I suspect another hatchet job, not least from an SNP supporting paper."

A University of Edinburgh spokesman said: "Professor Stephenson is an emeritus professor, meaning she is a professor who is retired. Professor Stephenson's views are her own."