Film director Woody Allen has denied that he sexually molested Dylan Farrow, the adopted daughter of his long-time companion Mia Farrow, when Dylan was seven years old.

The charges have been floating around for more than 20 years but, for the first time, the alleged victim has described the incident in graphic details in a public forum.

“When I was seven, Woody Allen took me by the hand and led me into a dim, closet-like attic… He told me to lie on my stomach and play with my brother’s electric train set. Then he sexually assaulted me,” Ms Farrow wrote in a letter on the blog of New York Times reporter Nicholas Kristof last Saturday.

A day later, Mr Allen used the same platform to hit back through his aide, Leslee Dart, who wrote that “Mr Allen has read the article and found it untrue and disgraceful.” Ms Dart continued: “At the time [of the alleged attack in 1992], a thorough investigation was conducted by court-appointed experts. The experts concluded there was no credible evidence of molestation.”

Ironically, or inconveniently, the charges are resurfacing just as the career of the director, aged 78, is hitting new heights. His most recent movie, Blue Jasmine, has received Oscar nominations, and there is a considerable buzz over his upcoming film, Fading Gigolo. In addition, he was recently fêted at the Golden Globes awards.

Mr Allen, born Allan Stewart Konigsberg in the Bronx, has made a career out of portraying nebbish Jewish New Yorkers, but that picture is at odds with his many romantic entanglements.

At 19, he married 16-year old Harlene Rosen and divorced her six years later. His next marriage, to Louise Lasser, lasted four years and he then wed Soon-Yi Previn, the adopted daughter of Mia Farrow. Mr Allen has also enjoyed “partnerships” with actresses Diane Keaton (1966-70) and Mia Farrow (1980-92). The latter breakup was acrimonious, and Mr Allen’s partisans claim that Mia was the real voice behind her daughter’s accusations.