Logan Michael Osborn, 19, pleaded guilty and was originally sentenced to 10 years in prison with eight years suspended by a judge in Chesterfield County, Virginia

But circuit judge Timothy J Hauler delayed the enforcement of the remaining two-year term in January, then stayed the prison sentence entirely this week.

Osborn will have to register as a sex offender and lost an academic scholarship to study chemistry at the University of Mary Washington because of the conviction.

Osborn pleaded guilty to having “carnal knowledge” of his victim in September, which is a crime in Virginia involving children between the ages of 13 and 15, in agreement that prosecutors would not pursue the more serious charge of “forcible sodomy”.

Osborn is alleged to have forcibly pushed the girl to her knees and tied a belt around her neck and hands before forcing her to perform a sex act.

She was untied before being picked up by her mother, who questioned her over what happened because of her distress and took her to hospital for forensic examination.

Defence lawyers claimed that the incident was consensual because the pair had discussed Fifty Shades of Grey beforehand planned to “have some fun” after the play, but prosecutors said the girl was taken advantage of, was too young to legally consent to sexual acts and that the suggestion was offensive.

A clinical psychologist classed Osborn as at “moderately high risk” for reoffending and the court heard that he had been accused of inappropriate sexual conduct with girls several times, being charged with grabbing a child’s genitals at the age of 12.

Judge Hauler has previously been criticised for several decisions relating to sex offenders. In 2016 he rejected Virginia state authorities’ request not to release a man jailed for raping his ex-girlfriend and suspected in many other sex attacks

The man, Dana William, later murdered his ex-wife’s father and killed himself before police could catch him.