An anti-independence Scottish MP has suspended his tour of the country after being pelted with eggs, citing security fears over "co-ordinated abuse" from the Yes voters.
Labour MP Jim Murphy was egged by a Yes supporter in Kirkcaldy, Fife, yesterday during his 100 Towns in 100 Days tour for Better Together.
He has called off the tour for 72 hours and is seeking police advice on whether to resume it.
He called on the Yes campaign to "call off your mobs," the BBC reported.
The Yes campaign has previously been criticised for the virulence of the online abuse dolled out by so-called Cybernats - who attack those who oppose independence on social media.
Mr Murphy said the tour had been "good fun" but recently had taken a "sinister turn for the worse".
"In the past 10 days or so, the Yes Scotland campaign has organised mobs to turn up at every meeting that I'm taking part in to try and silence undecided voters and to try and intimidate me," he told the BBC.
In response to the egging, David Cameron has said people who throw things at politicians should have no place in the democratic process.
He said: "I think the responsibility for the people doing these things lies with the people doing these things.
"I've always thought that it isn't right to throw eggs at people - I had one myself in Cornwall once, it's an interesting experience - and I'm sure other party leaders would take the same view.
"It's a vigorous debate with lots of argument, there's nothing wrong with a bit of heckling but throwing things isn't necessarily part of the democratic process."
First Minister Alex Salmond also condemned the egg throwing incident.
And he said a "road rage" incident, where he was tailed by another motorist waving a No sign at him, was a "very bad example" of what could happen in political campaigns.
But he said no responsible politician should seek to take advantage of such protests, as he insisted that the overwhelming majority of Scots were "enjoying the most invigorating, scintillating, exciting debate in our political history".
After independence campaigners staged a noisy protest outside a Glasgow hotel where Mr Cameron was speaking last night, Mr Salmond stressed the "right of peaceful protest", adding that people were "entitled to demonstrate outside a white tie function, the only safe audience the prime minister thinks he has in Scotland".
While he said people had "every entitlement to peaceful protest" he stated: "People shouldn't throw eggs at somebody full stop, that's something that happens in elections. I remember John Prescott getting a bit energised about it in a UK election. It shouldn't happen - I don't think it's at the serious end of things - but it shouldn't happen.
"The road rage incident was a very bad example but I don't make that an issue. I don't make the death threats from a few daft people I've had an issue, because I know know 99.9% of people in Scotland are enjoying and being energised by a wonderful political debate.
"All politicians should beware, yes of course we call for good conduct, on line and off line, yes of course we do. But don't confuse the actions of a few people with the 99.9% of the people of Scotland who are enjoying the most invigorating, scintillating, exciting debate in our political history.
"And don't try to take advantage of an incident, because I certainly wouldn't, and I'm sure no other responsible politician would want to do that."
In response to Mr Murphy's suspension of his tour, a spokesman for Yes Scotland said: "‘We condemn all forms of abusive, dangerous and offensive behaviour, whether it be Jim Murphy having eggs thrown at him, or Alex Salmond being harassed by a road rage motorist.
"For the most part, the independence debate has been conducted in a responsible, peaceful and enthusiastic manner with only a very small minority on both sides behaving badly.
"The eyes of the world are on Scotland and it is vital that everybody – regardless of which side of the debate they are on – helps to show off Scotland at its best."