Preston Crown Court was told that Constable Adam Grice-Roberts, 32, had been told to take the girl to hospital but had sex with her in the car in the police station garage at Blackpool, Lancashire.
The jury was told Grice-Roberts admits having sex with the girl but claimed she had persuaded him to do it. He has pleaded guilty to unlawful sexual intercourse but denies rape.
Guy Gozem, for the prosecution, said that the girl was "insensible" from inhaling gas, to which she was addicted. "She was in no condition to decide whether to consent or not," he said. "The prosecution say this fact was obvious."
The rape is alleged to have happened on 18 April when a woman found the girl - "apparently in another world" - and called the police. Mr Gozem said there was no dispute Grice-Roberts put her in his car where she carried on inhaling gas and that he had taken her to Blackpool police station where a sergeant advised him to take her to hospital.
"He walked her back to his car in the police station garage and in the back of the car had sexual intercourse with her there and then. He then drove her to hospital."
The girl, who cannot be named, had been to her parents' home in Blackpool for the Easter weekend and was due to return to a children's home in North Wales where she lived.
After Grice-Roberts dropped her at the hospital, she caught a train out of the resort. She was put off the service at Preston because she was seen inhaling gas. She ran away from a police officer and later that day made two phone calls to ChildLine.
The girl told a policewoman in video interviews that Grice-Roberts had touched her indecently while she was in the alleyway, putting his hand down her pants and asking her if it felt good. Mr Gozem said the girl had said no. She said on the video that the officer had let her carry on sniffing in the car, where he touched her again.
Mr Gozem said after they arrived at the police station they were sent away almost immediately by the sergeant. Grice-Roberts agreed that "there and then, almost immediately, he had sexual intercourse with her as she lay across the back seat of the car".
The girl claimed she was inhaling from a can as the officer had sex with her. Three empty cans were later found in the underground garage. The girl told police about her condition at the time: "I was really out of it."
Asked if she had told Grice-Roberts not to do it, she replied: "No, at the time I didn't even know what was going on. I was high. I knew he was having sex, but I was high."
Mr Gozem said Grice-Roberts's account to police was that the girl had consented to intercourse and that in effect she had persuaded him to do it. He claimed she had talked about it and said she wanted it, and touched him on the way back to the car "to leave him in no doubt she wanted sex".
Mr Gozem said from the description of other witnesses "it must have been perfectly apparent this girl was in no position to consent to sex".
Two video-taped interviews with her would form her main evidence and she would then be cross-examined by videolink.
The jury of seven men and five women watched on television screens set up in the court as the girl described in a taped interview what she claimed had happened when Grice-Roberts found her. She said: "I can't remember much. I was face down. I got up and carried on sniffing. He kept asking me why I did it."
She said the officer, who was in uniform, had put his hand down her pants. "He asked me if it made me feel good," she said. "I said no. He said, 'Carry on finishing your can.' Then he took me back to the car. He carried on touching me."
She claimed that in the dimly lit underground car park at Blackpool police station he had then had intercourse with her. "He did it. He had sex with me in the car," she said.
She then described how Grice-Roberts dropped her off at the Victoria hospital. She left without being treated after asking to use the toilet.
She went home, packed a bag to return to the children's home and caught a train for Preston, but ran off when she saw a policeman waiting at the station. She then phoned the children's helpline ChildLine and told them what had happened.
The girl said she had bought six cans of butane gas that day and had already sniffed three of them. She said: "I was high. I knew I was having sex but I was high. I am not lying."
The trial continues.Reuse content