When the lodger woke up the next morning he found the child alone in the house and the father nowhere in sight, the court was told.
When asked why he left his child alone for five days, the father told police it was to teach his son "independence", the Mirror reported.
With his father gone for five days, the 11-year-old boy said he followed the lodger around as he went about his business.
"The child said he would go with him and [the lodger] said he couldn't come as he was going to the pub," prosecutor Alan Morrison told the court.
The next day, while he was out, the lodger received a text message from the child asking when he would be home.
A day later, the lodger's work colleagues advised him to call the police after learning about his predicament.
"The child was found at school having got himself up, dressed and made his way there," Morrison said.
When the father returned home from Italy, the child had been placed in foster care.
The father was unapologetic when interviewed by police.
His son is in permanent foster care.
The father will be sentenced in November.
