TORONTO - More than a quarter century after Pierre Trudeau's iconic one-finger salute, the Ontario Film Review Board has added "flipping the finger" to its official list of crude behaviours.

The board, which classifies all mainstream films in the province, amended its manual so that the rude salute now will help knock a film from a General (G) designation into the Parental Guidance (PG) category.

The gesture, sometimes called "flipping the bird" or simply "the bird," is rated the equivalent of an animal humping someone's leg, according to the manual's section on assessing the psychological impact of mainstream films.

And the "finger" is now classified as one notch more obnoxious than "a little bit of farting, belching" in the crude behaviours category, in the latest edition of the manual, obtained by The Canadian Press under Ontario's freedom-of-information law.

The gesture, though, is considered less obnoxious than a teenager vomiting and his friend urinating onto bystanders, say the arcane guidelines in the 32-page document.

The denigrating digit has enjoyed a fabled place in Canadian political history ever since Aug. 8, 1982. That was the day Trudeau, then prime minister, gave the finger to each of three protesters awaiting him on the train platform in Salmon Arm, B.C.

The so-called Salmon Arm Salute or Trudeau Salute, caught by one television camera, soon became a vivid symbol for those who thought the Liberal prime minister arrogant and hostile to Western Canada.

But the Ontario film board, which classifies though rarely censors films, had not included the gesture among its detailed classification charts until last year.

The board strives for consistency and objectivity, and its manual provides precise instructions for its 19 reviewers, who each earn $380 a day, plus expenses, for watching and classifying new films based on community standards.

Sometimes, though, the board makes allowances for films that technically exceed the guidelines but are considered to have broader merit, so that a "bird" will not necessarily push a film into a more restrictive category.

For example, the critically acclaimed 2008 film by Ron Howard, Frost/Nixon, was found to contain three instances of a common obscenity (which the board terms the "F" word), plus one variation on that word beginning with "mother."

The rules say that first offensive word can be used "up to three times, or once per 30 minutes of the film's length" in a PG film, but the additional use of the "mother" word would push the film into the more restrictive 14A category, where viewers younger than 14 years of age must be accompanied by an adult.

However, the board took the rare step of exempting the film from the guideline and Frost/Nixon remained a PG, with a warning that "Language May Offend."

"There has been much discussion around the 3 F guideline in PG, this was raised in the 'Frost/Nixon' film. There were no elements other than the 3 F's and 1 M," say the minutes of a Nov. 28 review board meeting, also obtained under freedom of information.

"Please use discretion when classifying a movie such as this. Please take into account our audience and attach the appropriate content advisories."

The chair of the board said the "flipping the finger" gesture had long troubled reviewers, who were uncertain whether to count it as part of the "3 F" limit because it was a non-verbal way of saying the offending word.

"Should it count in our three? Or shouldn't it count in our three?" Janet Robinson said in an interview from Toronto.

"We've been skirting that sort of question for a couple of years. ... It just grew out of our continually talking about these things."

Robinson defended the position assigned to the "bird" along the board's rising scale of crude behaviours.

"Crude behaviour is farting, burping, all the things that nine, 10, 11-year-old boys love," she said.

"But it gets a little more intense when you start flipping fingers."

The board, which dates back to 1911, classifies about 1,500 mainstream films each year, charging fees to distributors for the service.

After several controversies over censorship, the board's authority to refuse films for screening in Ontario was substantially reduced in 2005 by the province's Film Classification Act.