A teenage girl who jumped from a bridge with a friend in an apparent suicide pact "regressed" when she was around her father, a fatal accident inquiry has heard.
Niamh Lafferty was 15 when she plunged more than 100ft to her death from the Erskine bridge with 14-year-old Georgia Rowe in October 2009.
The teenager was living at the Good Shepherd Centre in Renfrewshire after arrangements to stay with her father, Paul Lafferty, broke down and she refused to return to her mother, Collette Bysouth, in the family home in Helensburgh.
A social worker told the inquiry at Paisley Sheriff Court that Mr Lafferty, a recovering drug addict, lacked parenting skills.
Sandra Leonard, who worked at Argyll and Bute social services, said: "When she was around her dad she would regress a lot. She would almost be in his arms. She had to be with her dad."
She said the Lafferty family were "impulsive" and needed help to listen and engage with social workers while the Bysouths were "rational" and "would react to things in a calm manner".
Ms Leonard said: "He was too keen to please Niamh and had difficulties with boundaries."
Concerns were raised about Mr Lafferty's parenting by social services late in 2008, when his daughter was eventually barred from visits to her father.
Ms Leonard said Mr Lafferty did not seem to understand the need for Niamh to have a strict curfew, saying she "could come in when she wants".
They also expressed "serious concerns" about his apparent "encouragement" of the relationship between his daughter and her boyfriend, Jonny McKernan, 16.
Ms Leonard said it was felt the relationship was "inappropriate" as Niamh was three years younger and he was "involved in a lot of problems in the community", including crime and drug use, and there was a history of "domestic violence" in his relationship with Niamh.
The inquiry, before Sheriff Ruth Anderson, continues on Monday.