A boss and his secretary who were having an affair saw their romantic tryst interrupted in a wince-inducing manner - after a car crash led her to accidentally bite his penis off.

According to reports in China Press and Sin Chew Daily, the 30-year-old woman was performing oral sex on her boss in a car in a Singapore park, when the car was struck by a reversing van.

The impact caused her to bite the man's penis off.

Just in case this wasn't already bad enough for those involved, the incident was observed by a private detective who had been sent by the woman's husband to catch them out.

He described how, shortly after parking, the car started to 'shake violently' - but then was hit by the van. He said that the woman screamed loudly, with her mouth covered in *lo**.

Helpfully, the investigator called an ambulance to take the man to hospital. His lover followed him there, with part of his penis.

The investigator said he's never seen an incident like it before.