Don Maguire was speaking to the BBC on the back of a report earlier this month, which said nothing could've been to prevent Ann Maguire's murder at Corpus Christi Catholic College in Leeds in 2014.
Mrs Maguire, 61, was celebrating her 40th year teaching at Corpus Christi Catholic College in Leeds when she was stabbed during a Spanish lesson by Will Cornick.
The teenager had threatened to kill the mother of two in social media posts and told peers he also planned to murder his head of year and another teacher and her unborn baby.
Cornick (below) was jailed for life with a minimum of 20 years after pleading guilty to the murder, which was the only time a teacher has been killed by a pupil in a UK school.
The report by independent reviewer Nick Page, who interviewed the teenager, concluded: "What is clear to me, as the reviewer, is that no one could have predicted or pre-empted Will Cornick's attack on Ann Maguire.
"No individual other than Will Cornick should in any way feel responsible for Ann's murder."
Will Cornick has admitted murdering Ann Maguire
But Don Maguire said that until all the circumstances of her death were fully appraised "it's possible that lives could be at risk in British schools".
He went on: "This shouldn't be about trying to make everything seem okay and hoping it doesn't happen again.
"They're going through all this time and expense to find partial answers to these questions. If we really want to learn and protect teachers and pupils we have to know every detail of this case.
"For a teacher to be murdered by a pupil in a classroom in the UK means it should be treated in the most serious of manners.
"These kind of learning lessons reviews are always done when terrible events happen, and the departments always say it could have been prevented but not predicted. It feels like they've done the bare minimum."
