A Metropolitan Police officer has been sacked after a misconduct hearing found he formed an "inappropriate relationship" with a 14-year-old girl.
Pc Robert Nicholson met the girl in October 2009 while she was in custody and exchanged text and Facebook messages which had "sexual elements".
He then met the girl when he took her out of her care home in east London.
The constable, who was 27 at the time, faced a trial for sexual activity with a child but was found not guilty.
An Independent Police Complaints Commission (IPCC) found he first met the girl at Bethnal Green Police station, where he was working as the jailer, when she had been arrested.
After Pc Nicholson got her number they exchanged hundreds of messages and regularly spoke by phone.
On 16 December 2009 he drove from his home in Colchester, Essex, to meet the girl at her care home in Romford.
Staff at the home reported her missing and one of the girl's friends told staff she was with a police officer. The officer returned her near to the home later the same day.
Deborah Glass, the IPCC commissioner for London, said: "We expect the police to protect us and our families, yet Pc Nicholson's actions were, from the outset, a disgraceful abuse of his position.
"Although he met the girl while she was in police custody, and there can be little doubt he knew her age and vulnerability, he exploited his position as a police officer to pursue her sexually.
"I am glad he is now no longer in a position to do this to anyone else."
Pc Nicholson stood trial on two counts of sexual activity with a 14-year-old child last November.
This related to allegations arising from the time the girl was away from the care home in December 2009.
He was found not guilty of both charges after a five day trial.