BURGER King made a whopper of an error with a tweet “condoning” the “milkshaking” of Nigel Farage, advertising watchdogs have ruled.

The Advertising Standards Authority (ASA) has censured the fast food chain over a social media message posted in May as the Brexit Party head prepared to address a rally in Edinburgh.

It followed a spate of dairy-based incidents involving right-wing politicians.

English Defence League founder Tommy Robinson and UKIP candidate Carl Benjamin had both had milkshakes thrown on them in the weeks preceding the tweet.

And though a McDonald’s outlet near Edinburgh’s Corn Exchange put a temporary stop on shake sales after a “police request”, the rival chain tweeted: “Dear people of Scotland. We’re selling milkshakes all weekend. Have fun. Love BK. #justsaying.”

More than 20 people complained to the ASA, saying it encouraged anti-social behaviour. Burger King – which has outlets in Ayr, Kinross, Gretna Green and more – said the comment was “tongue-in-cheek” and a follow-up message told Twitter users: “We’d never endorse violence – or wasting our delicious milkshakes! So enjoy the weekend and please drink responsibly people.”

But today the watchdog has banned the tweet after an investigation.

In a statement, the ASA said: “Although we acknowledged that the tweet may have been intended as a humorous response to the suspension of milkshake sales by the advertiser’s competitor, in the context in which it appeared we considered it would be understood as suggesting that Burger King milkshakes could be used instead by people to ‘milkshake’ Nigel Farage.

“We considered the ad therefore condoned the previous anti-social behaviour and encouraged further instances. We therefore concluded that the ad was irresponsible.”

The standards body continued: “We told Burger King to ensure that its future marketing communications did not condone or encourage anti-social behaviour.”

Farage, who was once helped from an Edinburgh pub by police after protesters gathered outside, was in the city ahead of the European Parliament elections.

Care home director Louis Stedman-Bryce was returned as the Brexit Party’s sole Scottish MEP.

While Farage was not “milkshaked” during his Edinburgh visit, that did happen during a walkabout in Newcastle days later.

When the Chesser McDonald’s branch told customers they would refuse to serve the daily drinks or portions of ice cream, Police Scotland refused to comment. However, one staff member, who did not want to be named, called the situation “ridiculous”.

Robinson, whose real name is Stephen Yaxley-Lennon, was hit twice in two days in the north west of England and Benjamin, a YouTuber, was targeted at a public meeting in Cornwall.