A convicted sex offender stayed at a house in Nelson, where a young child was present and didn't tell the police, a court heard.
Anthony Herdman was supposed to tell officers if he had contact with a youngster for more than 12 hours.
The 24-year-old was on the sexual offenders' register, after being convicted of sexual assault in 2016, Burnley magistrates were told.
Miss Parveen Akhtar, prosecuting, said police went on an unannounced visit to Herdman's home in Burnley and were told by his father that he had moved out and was living at an address in Nelson.
Officers went there and spoke to him and he confirmed he was living there. Miss Akhtar continued: "It was then discovered there was a young child at that address."
The defendant was arrested and in interview he said he had forgotten to register the child contact.
Mr Mark Williams, defending, told the court Herdman and his father had not been getting on and he had gone to the Nelson property. The solicitor continued: "He certainly wasn't living permanently elsewhere, but he had started to spend the night now and again there."
Mr Williams said the Nelson householder was fully aware of the defendant's convictions and background. He went on: "There is no suggestion in the officer's statement that they were concerned that he had been there or that he was hiding anything from them."
The solicitor added Herdman suffered from foetal alcohol syndrome because of his mother's drinking. Mr Williams added: "He can't, for example, read or write."
The defendant, of Hart Street, Burnley, admitted failing to comply with the notification requirements of the sexual offenders' register, on December 3rd.
He was given a six-month community order, with a 10-day rehabilitation activity requirement and was fined £10.