Sure, flamboyant British artist Sebastian Horsley has done loads of drugs, had sex with hookers, worked as a prostitute himself and was once voluntarily nailed to a cross—but, according to PEN, the prestigious New York literary group, the US government is dead wrong in banning him from coming here to promote his new X-rated autobiography.

PEN has consulted lawyers to take up the battle for Horsley, who was refused entry after arriving at Newark Airport last month to promote “Dandy in the Underworld,” a sex—and drug-filled tell-all from Harper Perennial that rocker Bryan Ferry praised as a “masterpiece of filth.” Customs cited a federal statute under which foreigners guilty of “moral turpitude,” including admitted drug use or twisted sexual peccadilloes, can be turned away.

“It must look so hypocritical to the world. The US floods the planet with its cultural products, and then they do this. It’s an embarrassing mistake,” PEN’s Larry Siems told Page Six. “We’ve written the Department of Homeland Security, and we hope they’ll do the right thing.”

From his home in London, Horsley told us: “I’m no sort of threat to national security. The only thing I’m a threat to is myself! I flew eight hours to get there, was interrogated for eight hours, then had to fly eight hours back. I don’t think anyone in the history of aviation has flown so far and so long to go nowhere!” He notes he visited the US a few years ago without any problem. “Is there such a thing as an immoral book? I don’t think so,” he said, cheekily adding that reading his tome is “like bathing in someone else’s dirty water. It’s filthy!”

In its letter to the feds, PEN writes: “[This is a] dangerous precedent that could be extended to bar scores of literary figures from a number of countries who challenge conventional mores.” Past authors who’ve faced the “moral turpitude” clause include Gabriel Garcia Marquez, Doris Lessing and Dario Fo.

Horsley—who was infamously crucified on a cross in the Philippines six years ago as part of an art project and whose advice column in London’s Observer was yanked for its graphic descriptions of oral and anal sex—told us: “Hopefully, the PEN is mightier than the sword!”