Richard Farnell told a panel that he did not know about claims of widespread sexual exploitation in the town between 1986 and 1992.
His refusal to accept responsibility for events was described as “shameful”.
Mr Farnell claimed his colleagues had not informed him of claims that boys as young as eight at the council-run Knowl View school and Cambridge House Hostel were being sexually targeted by men from as far afield as Sheffield.
But the panel said it “defies belief that Mr Farnell was unaware of the events involving Knowl View school.”
The Independent Inquiry into Child Sexual Abuse concluded on Thursday that authorities showed a “total lack of urgency” to address exploitation at the school.
Professor Alexis Jay, who chaired the inquiry, said she was “deeply disturbed at the evidence of extensive abuse and the institutional responses to that abuse”.
“Many of those who testified to their abuse have never had the opportunity to see justice through the courts,” she added.
The inquiry report also found that opportunities to prosecute Cyril Smith – the late Liberal MP believed to have perpetrated abuse – were missed.
There was an “unwillingness of those at the highest level” to believe a prominent figure was capable of child abuse, the inquiry concluded, while boys at the school were regarded not as victims but “authors of their own abuse”.
It heard that Smith, who received a knighthood despite a string of sex allegations, showed a considerable interest in children in care as his political career progressed.
Witnesses reported that he sexually assaulted them on the pretext of medical examinations.
A Lancashire Police file detailing evidence against Smith was given to the Crown Prosecution Service in 1998 – but they advised no charge should be faced despite there being a “realistic prospect of conviction”.
A CPS spokesperson said their approach to such cases was now very different and lawyers would likely have charged Smith if considering the same evidence today.
“Since those decisions were made, training and guidance for prosecutors handling child sexual abuse and rape cases have been subject to huge change,” they said.
The inquiry did not find evidence of a cover-up, however.
Daniel Wolstencraft, a member of the inquiry’s victim and survivor consultative panel, called the findings “momentous”.
“These lads from the age of nine up to 11 came forward… and they have been branded liars,” he said.
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“Richard Farnell has been called out, he’s been called a liar, he’s been proven to be a liar, the 360 turnaround is that’s what happened to these lads.
“A lot of these lads aren’t with us any more, a lot of these lads have taken their own lives.”