Lewis Hamilton's decision to dump his father and sign up with a celebrity management company was "a disaster".
That is the view of F1 chief executive Bernie Ecclestone, speaking after arguably the worst season in the 2008 world champion's entire motor racing career.
He said the 26-year-old Briton's "personal problems" in 2011 - including his split with girlfriend Nicole - were exacerbated by the absence of his former manager and father.
Anthony Hamilton, in charge of his son's career until early 2010, now manages the Force India driver Paul di Resta.
"A lot to do with these things, it depends an awful lot on the people you surround yourself with, and who are in a position to influence you," said Ecclestone.
"I think he just fell into a lot of people that I think weren't good for him," the 81-year-old told the Guardian.
"When his dad was looking after him, his dad was a bit more ... obviously it didn't suit Lewis, which was why they split, I think he didn't appreciate how much help his dad was," said Ecclestone.
After the split with his father, Hamilton linked up with XIX Entertainment, the company headed by Spice Girls manager Simon Fuller.
I think he just fell into a lot of people that I think weren't good for him
"I think it's a disaster," said Ecclestone. "He gets to meet people that probably he wouldn't have met, and (who) have probably the wrong sort of influence on him."
He mentions Ice-T, the rapper who made a controversial video inside the McLaren garage in Canada this year.
"He (Hamilton) sees somebody like that, he admires the guy, so he'll start copying a little bit what they're up to," said Ecclestone.
British commentator and former McLaren driver Martin Brundle agrees that Hamilton needs to get his "mindset" right after a calamitous 2011 season.
"Any sport is 90 per cent in the head. That's what he needs to get right," he is quoted by The Fun.