A former US Secret Service operative who specialised in protecting politicians from unknown substances has told Nigel Farage to “keep a change of clothes handy and man up” after the Brexit Party leader was doused in milkshake as part of a growing protest against figures on the right. 

Dan Kaszeta, who served as a senior physical security specialist under president George W Bush, suggested the rise of “milkshaking” should be considered a form of protest and “not political violence”, unless there was evidence it was intended to cause harm.

Anti-Islam activist Tommy Robinson, Ukip candidate Carl Benjamin and Mr Farage have been repeatedly targeted by people brandishing milkshakes in recent weeks.

The trend has led to an increasingly polarised debate as to the limits of legitimate protest, and whether throwing soft drinks at divisive political figures could lead to more dangerous tactics in future. 

A number of politicians have condemned the practice, including Change UK MP Anna Soubry, who called it “unacceptable and wrong”. Mr Farage blamed his milkshaking on “radicalised remainers” and politicians who were “not accepting the referendum”. 

Others, however, have claimed food throwing has a rich history as a form of protest and has rarely led to more violent forms of demonstration.

Mr Kaszeta, who advised the White House on how to respond to unknown dangerous substances, said nearly all instances of food throwing should be considered a form of protest rather than violence. 

Click on the Twitter icon below to expand the thread

“Nearly all of the time an egg is an egg, and a milkshake is a milkshake.  We, in the [Secret Service], on President Bush, in the post 9/11 era didn't consider that stuff to be ‘political violence’ in the absence of evidence of intent to cause actual harm,” he tweeted. 

“We had eggs thrown. We had powder thrown. We had drinks thrown. I had a frappucino thrown at us in a motorcade. Mostly, this stuff never made the press, George Bush had a valet with a spare suit and a good attitude.

“FFS, Nigel, Carl, Stephen. You got a whole posse of handlers and factotums. Keep a change of clothes handy and man up.

Milkshaking: New tactic emerges in fight against far-right

Show all 6

“What some fail to understand is that this is not a binary all or nothing, black or white thing. There's a whole lot of grey area in a spectrum between completely innocuous funny s*** and actual physical violence. And a milkshake is towards the former, not the latter.”

On Tuesday, police said they had charged a man with common assault and criminal damage following the dousing of Mr Farage while on a walkabout in Newcastle city centre.

Mr Farage’s suit was left covered in the drink after the incident at about 1pm on Monday and he was quickly hurried away from the scene by staff.