CUT her f***ing head off". "Punchable gobshite". Comparisons to Nazis and Hitler and fake accounts which portray the SNP MP Natalie McGarry in pornographic adverts.

These are just some examples of the vile abuse uncovered by the Sunday Herald which has been directed against SNP members, politicians, supporters and anyone in favour of independence by unionist opponents.

Among the most shocking cases is that of tennis star Andy Murray: an open supporter of Scottish independence, he was told by one Twitter user he should have been killed during the Dunblane massacre for being an "anti-British hypocrite". He was a pupil at the school at the time of the attack.

The culprit is understood to have deleted their account following the abuse, before another with the same name was opened up in its place.

The SNP itself has been described many times as the Nazi party, with commenters comparing Nicola Sturgeon and Alex Salmond to Hitler (@RAB9872), and their party's logo to swastikas (@peterDawson0).

@Rab9872 said he stood by his comments when we contacted him, but added: "I'm certainly not saying SNP will commit the atrocities the Nazis did but they are similarities." @PeterDawson0 was no longer on the social media site.

One Twitter user, @cboulter49, wrote they wished they could send the First Minister "to ISIS" and added: "They will sh** anything, then they wud [sic] cut her f***** head off." They did not respond when asked for a comment.

The actress Frances Barber

(@francesbarber13), who did not reply when asked for a response, said that England would wage civil war on the "racist SNP".

The contents of the unionist trolling vary - from swear words, aggressive language and threats, to continuous harassing messaging and name-calling. Their impacts have differing effects on their victims, too. Recently-elected MP McGarry, who represents the Glasgow East constituency, said she has had to have six accounts taken down from Twitter which were impersonating her, insulting her and abusing other people online in her name.

She said: "People insult my intelligence, the way I look ... One of the [fake accounts] had taken to cutting my head out and putting it on to the bodies of naked women, fat women, all different things. The first three accounts I had taken down were using my name, using my picture, nothing to say they were a parody except the abuse.''

McGarry said one troll had tried to enter her parliamentary email address to legitimise the account, which she was notified of when she checked her email. She said: "They were just vile. One of them had an advert that said 'I can go all night for £3' with my head attached to the top of it. Just horrendous stuff, week in week out."

The MP said she fears the online abuse is deterring women in particular from engaging in politics and making their voices heard for fear of sexist, misogynistic repercussions, but added she "won't be silenced, or forced off the internet" by the bullies.

"We get it a lot worse than the men ... There's this attempt to put them [women] back into boxes, silence them."

Mike Small, the founder of pro-independence news website Bella Caledonia has also been threatened and smeared online.

"I considered contacting the police but decided not to and - maybe stupidly - tried to handle it myself," he said.

The first incident happened when Small gave a talk on the effects of social media and activism before the independence referendum.

He said: "That was about the time when Rangers were going into liquidation and there was a campaign on social media by other supporters that they weren't going to get parachuted back into the top league.

"That's the example I used. I then had a photograph someone had taken in the audience posted on social media, it was pretty clear they were saying, 'I was there, we know who you are.'

"I have small children and I felt it was quite threatening. It forced me to withdraw a bit and lower my profile for a period, but I thought eventually 'I can't have that' and I came back.

Scots playwright Alan Bissett has also come under fire on Twitter with people name-calling and openly threatening him. He was called a "punchable gobshite" during the independence referendum campaign, with others making abusive sexual comments.

"It's important to distinguish between political opponents who express themselves politely or might have a valid argument and trolls who are just out to wind you up and trick you into losing your head," Bissett said.

"I can spot the trolls immediately -they'll have Union Jacks or #SNPout all over their profile or they've got very few followers. They come out with a charge-sheet of things of which I'm not guilty - being a bigot, anti-English, SNP lapdog, the usual - just for believing that decisions about Scotland should be made in Scotland.

"I've been called 'fat' plenty of times and there have been homophobic comments about the way I dress. Sometimes it's worse, but those people you just block immediately."

One so-called "cybernat" linked to First Minister Nicola Sturgeon in an article in the Daily Mail last week was Robert Dickson, who has tweeted about former Tory employment minister Esther McVey saying: "I have never used this epithet towards a woman ...but Esther McVey is a c***."

Yesterday, Dickson told the Sunday Herald: "I'm not a 'mad vile cybernat'. Whilst the tweets I posted were not my finest hour, I'm better than that. Sometimes I let passion get the better of me."

Dickson said he had met Sturgeon on two occasions, once through his job when she came to a union event, the other when he spotted her at Queen Street station one day while waiting with his son.

He said: "That's [where] the only association with me came from. I sent her a tweet saying it was really nice to meet you, the other guy was my son.

"She replied saying it was lovely to meet you, and that's the extent of my interaction with Nicola Sturgeon. She has no idea what I'm writing or tweeting, she doesn't know me from Adam."

Jill Stephenson, a historian, prominent unionist and emeritus professor at the University of Edinburgh who goes by the twitter name @Historywoman, last week posted it was "no surprise" that a man who was ejected for being drunk and disorderly on a flight was from Dundee as it was "a Yes city".

When asked by the Sunday Herald if she stood by the remarks, Stephenson said: "What I said was actually rather low-key. But I appreciate that popular newspapers have to paint things in dramatic terms. I realise that there are a lot of people on Twitter who hate me. Their problem is that I really don't care about what they think about me.

"With people who appear on my timeline simply for the purpose of insulting me - which some nationalists do - I mute or block. They are a waste of time."

Stephenson has also referred to independence supporters as "w*****s" and called regular trolling victim Natalie McGarry a "stupid woman".

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."

Our investigation comes in the same week Scottish Labour produced a dossier detailing online abuse from SNP members and independence supporters.