You may find this utterly unbelievable, but schools have no legal obligation to report suspicions, allegations or even known incidents of abuse to the authorities. A headteacher can know for certain (because it has been admitted to him) that a teacher has raped a pupil on school premises, but the head has no legal obligation to report anything to anybody.
This school when it caught an abuser, went to the trouble of consulting its lawyers to see if it had to report the abuse. The lawyers said no.
The police stumbled across the case 20 years later. The abuser got 5 years. The school was not prosecuted - it had not broken any laws.
So if you are considering sending your child to an independent school, look carefully at the school's child protection/safeguarding policy. What you want to see is an absolutely unequivocal promise that all child protection concerns will without exception be promptly reported to the authorities.
Look out for weasel words. For instance "should" leaves discretion as to whether they actually will or not. "In all appropriate circumstances" is another favourite, because they don't describe what kinds of circumstances are appropriate, so they can make that up as they go along. Read the policy from the point of view of somebody who might want to twist the words to find excuses not to report. Many schools don't want to report because an abuse scandal can be very bad for business.
The law hasn't changed on this in decades. There have already been reports in the news that Southbank International School was aware of at least one incident of concern about William Vahey but did not report it. I've looked at the Southbank child protection policy, it is on the school website. It clearly allows allegations of abuse by staff to be handled in-house if the school chooses.
It took me four years of solid campaigning to get my son's old school to reform its safeguarding policy. Abuse had gone unchecked there for 60 years (fortunately my son was not a victim). Three former teachers have been convicted. You can read about it here.
If you think this legal state of affairs is unacceptable, then please sign these petitions.
Daniel's Law
Mandate Now