Child sex abuse is "woven, covertly, into the fabric" of British society, Theresa May has warned.
The Home Secretary said the announcement this week of panel members and new terms of reference for the Parliamentary inquiry into historical abuse marked a "new beginning" for the probe.
But she said the public are yet to grasp the full scale of the scandal, with the allegations so far amounting to the "tip of the iceberg".
Writing in the Daily Telegraph, Mrs May said: "We already know the trail will lead into our schools and hospitals, our churches, our youth clubs and many other institutions that should have been places of safety but instead became the setting for the most appalling abuse. However, what the country doesn't yet appreciate is the true scale of that abuse.
"In my discussions with older victims and survivors and their representatives, I began to realise how abuse is woven, covertly, into the fabric of British society.
"During one of my first meeting with survivors, one lady said to me: 'Get this inquiry right and it will be like a stick of Blackpool rock. You will see abuse going through every level of society.' I fear she is right. I have said before and I shall say again, that what we have seen so far is only the tip of the iceberg."
The inquiry was established last July to find out whether public bodies had neglected or covered up allegations of child sex abuse in the wake of claims paedophiles had operated in Westminster in the 1980s.
Mrs May dissolved the original panel after two chairs were forced to stand down over their links to Establishment figures from the 1970s and 80s, appointing a new chair and re-examining the terms of reference.
Last week it was announced Professor Alexis Jay, who led the report into abuse in Rotherham, Drusilla Sharpling, Ivor Frank and Malcolm Evans will serve alongside Justice Lowell Goddard, a New Zealand judge, on the wide-scale inquiry.
New terms of reference for the inquiry were also agreed, including a removal of any cut off date for claims which can be investigated by the probe.
Mrs May added she felt it was a "once-in-a-generation" chance to uncover institutional abuse, which she called "the darkness in our midst".
After Rotherham, ‘200 child sex victims in East Riding’ 27 FEBBRAIO 2015