A man has received £500 in compensation after wrongly being made to register as a sex offender for taking photographs of his girlfriend's five-year-old son.
The man, known as "M" for legal reasons, was arrested last year after a member of the public saw him taking photos in Longford Park, Coventry.
However, a High Court judge ruled West Midlands Police were wrong to caution him as it violated his human rights.
The caution was quashed, automatically removing his name from the register.
Mr Justice Wyn Williams said no evidence existed that would have justified charging M with any criminal offence.
He added that the caution unlawfully interfered with M's right to a private life, contrary to Article 8 of the European Convention on Human Rights, over a substantial period of time.
The court heard that 24-year-old M, a male friend and his girlfriend, known as "E" at the court hearing, were arrested on suspicion of being involved in making indecent photographs of a child.
The three had gone to the park in September last year and a member of the public contacted police after seeing M taking photos of the five-year-old who had taken his clothes off.
After being interviewed, M was released on bail on condition that he reported daily to a certain police station and stayed at a particular address.
M's girlfriend and the male friend were also released.
But the boy was taken into the care of the local authority and M was banned from any unsupervised contact with him, the judge said.
M, who speaks Kurdish, was given a caution in December but without an interpreter and any legal representation.
After a judicial review and his solicitors successfully arguing that there was not enough evidence for a caution, the police force's chief constable accepted that the caution must be quashed but said awarding damages was unnecessary.
But the judge disagreed and said interference with M's private life had gone on for a significant period of time and he was entitled to receive his legal costs as he had been "wholly successful" in his legal challenge to the caution.