A McDonald’s outlet near to where Nigel Farage was speaking was stopped by police from selling milkshakes because of fears protesters would throw the dairy-based drinks over him.

Staff said officers had ordered them to take action to avoid repeats of scenes when Ukip candidate Carl Benjamin and activist Tommy Robinson both had milkshakes hurled at them this month.

Anti-far-right campaigners have quickly adopted the tactic of throwing milkshakes during the European elections in attempts to humiliate those they disagree with.

Brexit Party leader Mr Farage was talking to supporters at a campaign rally at the Edinburgh Corn Exchange on Friday.

Workers at the McDonald’s less than 200 metres away put up signs in the window and on the counter saying: “We will not be selling milkshakes or ice cream tonight. This is due to a police request given recent events.”

Milkshaking: New tactic emerges in fight against far-right Show all 6 1 /6 Milkshaking: New tactic emerges in fight against far-right Milkshaking: New tactic emerges in fight against far-right Newcastle says "no thanks Farage" Brexit Party leader Nigel farage is led away by security after being hit with a milkshake at a campaign event in Newcastle Reuters Milkshaking: New tactic emerges in fight against far-right Tommy Robinson covered in a milkshake... While out on the campaign trail for the European Elections in Warrington, a man threw a milkshake in Tommy Robinson's face. Frame 1: Man throws milkshake. Frame 2: Robinson and Co. beat man. Frame 3: Robinson covered in milkshake @AzTheBaz/Twitter Milkshaking: New tactic emerges in fight against far-right ...the day after being covered with a milkshake The day before in Bury, a suspected child threw a milkshake over Robinson before running away Paul Ryder/Youtube Milkshaking: New tactic emerges in fight against far-right Gerrard Batten's image Amy Thompson from Plymouth greeted the Ukip tour bus by throwing a milkshake over the image of leader Gerrard Batten McCoys Media/SWNS Milkshaking: New tactic emerges in fight against far-right Carl Benjamin milkshaked Ukip candidate Carl Benjamin aka Sargon of Akkad was met with a milkshake while campaigning in Totnes, Devon PA Milkshaking: New tactic emerges in fight against far-right Aftermath The remains of the milkshake that struck Carl Benjamin Cornwall Live/SWNS

But rival chain Burger King encouraged customers to buy milkshakes, tweeting: “Dear people of Scotland. We’re selling milkshakes all weekend. Have fun. Love, BK”.

When one Burger King follower asked whether it was because Mr Robinson was in Scotland, the company replied: “No comment”.

Earlier, several people had tweeted that a McDonald’s selling milkshakes was “conveniently” close to where Mr Farage was speaking.

One told the fast-food giant: “This is the wrong approach, free milkshakes and ice creams on the day instead!”

Police Scotland refused to comment on the apparent demand but a member of staff, who did not want to be identified, described the situation as “ridiculous”.

Mr Benjamin, who is being investigated for threatening to rape MP Jess Phillips, had three milkshakes thrown at him in as many days as he toured the southwest of England.

And Mr Robinson, whose real name is Stephen Yaxley-Lennon and who is standing as an independent candidate, was hit with milkshakes twice in two days in Bury and Warrington earlier this month.

Political agitators traditionally used eggs to pelt at politicians they hated, but it’s believed that they have now switched to milkshakes because unlike eggs, they do not raise suspicions.

Experts say the light colour and frothy nature of milkshakes also appeals to campaigners because when thrown they contrast with politicians’ often dark suits.

Benjamin Franks, of the University of Glasgow, who specialises in direct action, said the alt-right had used milk as a symbol of white supremacy because of its whiteness, and to mock people with a “genetic predisposition” to lactose intolerance.

Such medical intolerances have been found to be higher among people of Asian and African origin.

“The milkshake is turning that symbol against them [right-wingers],” Dr Franks told The New Statesman. “It is an example of political ju-jitsu. It also makes them look foolish, undermining their self-image of power and control. The bathos of the great leader brought low by a drink associated with children is highly effective.”

In 2013 Mr Farage was forced to take refuge in a bar in Edinburgh’s Old Town after he was swarmed by angry protesters as he left a press conference.

On Friday, having returned to the Scottish capital, he vowed to cause an “earthquake” in politics and appealed to SNP voters who backed Brexit in 2016 to “lend him” their votes.