The lesson for Jerry Falwell is simple: always, always, always, check over your shoulder before posing for a photograph.

The Evangelical Christian and president of Liberty University found himself at the centre of no small amount of mockery after he posed for a photograph with Donald Trump, against a backdrop that included a copy of Playboy, the soft porn magazine. What's more, the magazine cover featured Mr Trump and a model now serving jail time for cocaine smuggling.

Mr Falwell was an early endorser of Mr Trump and invited him to speak at his private Christian college in Virginia. In a speech to students, Mr Trump fumbled a reference to the bible.

Mr Trump appeared on the cover with Brandi Brandt, who is now in jail for cocaine smuggling (Playboy)

Mr Falell later said of his decision to back the New York tycoon: “I did so because the country is at that point.”

The leg-pulling began after Mr Falwell tweeted a photograph of himself and his wife, Becki, posing with Mr Trump in his New York office. What Mr Falwell had apparently not spotted were the series of framed magazine covers on the wall, among them a copy of Playboy, featuring Mr Trump and model Brandi Brandt on the cover.

Brandt, who was once married to Motley Crue bassist Nikki Sixx, is said to have been a regular visitor to Mr Trump’s New York offices during the 1990s, was two years ago sentenced to six years in jail for her role in a drug smuggling operation.

Critics of Mr Trump and Mr Falwel’s support for him, were quick to point out the irony of the conservative Christian college leader posing in front of a men’s pornographic magazine.

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The New York Daily News said that the image was especially ironic given that Mr Falwell’s father, Jerry Falwell Sr, famously sued Hustler magazine publisher Larry Flynt for a satirical depiction of him in his porn magazine, in a case that landed in the Supreme Court. (Mr Falwell lost the case.)

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Mr Trump is reportedly proud of the March 1990 Playboy cover. Last month at a rally in Pennsylvania someone handed him a copy of the magazine to autograph as he worked the rope line and he held it to show to his cheering supporters.

On Tuesday night, Mr Fawell responded on Twitter by likening the criticism he had received to the travails endured by Jesus.