The United Airlines service was scheduled from Denver to Baltimore, but ended up in Chicago after the pilot changed course due to “security concerns”, the Atlantic reports .

The flight, which took off on February 2 this year, was showing the 2012 crime thriller Alex Cross, which is rated “15” in Britain. In the US, it had the “T” classification, which warns of adult themes.

According to the family making the complaint, the film was screened on drop-down screens, which meant they could not shield their two children, who were aged four and eight, from its content.

They have described how they first asked flight attendants for it to be turned off at the monitor, then asked if the captain had the means to do so.

Nothing happened for more than an hour, they claimed, leaving them trying to divert their children's attention from scenes they described as “horrific”.

The pilot then announced the plane would be landing at Chicago due to “security concerns.”

At the airport, the family were briefly interviewed by police and border protection officers, before being placed on a later flight.

The father, whose name has not become public, accused the captain of “abuse of power”, and criticised the airline for showing “grossly inappropriate cinematic content.”

Charles Hobart, the United Airlines spokesman, confirmed the flight had been diverted “after the crew reported a disturbance involving a passenger.”

He added: “We re-accommodated the customers on the next flight to Baltimore and have since conducted a full review of our in-flight entertainment.”