The 25-year-old woman was too frightened to tell the authorities for three months because her then boyfriend - also a police officer - was a close friend of the alleged rapist, a jury at the Old Bailey was told.
PC Michael Seear, 25, denied committing the rape, which allegedly took place in the early hours of New Year's Day last year at a police section house of the Surrey police force.
Peter Clarke, for the prosecution, said that before the attack Mr Seear, of Lightwater, Surrey, and his alleged victim were good friends and he was normally "impeccably behaved", but on the night of the party the defendant got extremely drunk.
The court was told that after the party and while waiting for her boyfriend the woman had helped Mr Seear back to his room.
There, the woman said: "He just suddenly turned and locked the door. Then he just grabbed me round the waist and neck and tried to kiss me.
"I was saying `What are you doing - stop it.' He was really weird. It was like it was not him." Mr Seear then allegedly attacked the woman, pushing her on to the bed where she hit her head on the wall. He then allegedly raped her.
"It felt as if I was screaming all the time - but something made him stop abruptly and he got up," Mr Seear allegedly told her she had better go. The following morning, he had allegedly visited her room and told her: "I am really sorry. It will never happen again."
"During the day she felt in a complete dilemma," Mr Clarke said. "She knew the consequence of complaining. It would cut across the friendships there to a startling degree."
It was not until three months later that a formal complaint was made, Mr Clarke said.
Mr Seear insisted he had never had sexual intercourse with the woman or caused her injuries.
The trial continues today.Reuse content