A "national epidemic" of sex abuse has hit the UK with as many as 11 million victims, an expert warned today.
Graham Wilmer, who has been appointed to a government inquiry on the issue, said his estimation was based on "prevalence rates published by the Government".
The founder of sex abuse support charity the Lantern Project was appointed by Home Secretary Theresa May as an independent panel member on the controversial historical sex abuse inquiry.
Its start has been overshadowed by the resignation of two chairman and anger from some victims themselves.
Mr Wilmer, an abuse victim himself, told Sky News: "There are potentially about 11.7 million victims out there at the moment who have not disclosed, and many of those people will start to come forward in very significant numbers."
"You are dealing with a massive, massive problem. From what we have seen, if you don't provide the right level of support and intervention to support people when they come forward you see very significant health problems, mental health and physical health, which have a direct cost to us as a society.
"We look upon child abuse and it's impact now as a national health epidemic."
Children's charity the NSPCC estimates one in 20 children in the UK have been sexually abused.
The Government's inquiry has been dogged with problems since it was announced in July. Two chairmen have been forced to step down after links to the Establishment cast doubt among victims as to their suitability for the role.
Mrs May has apologised to victims for failing so far to find a suitable person to fill the role.
Baroness Butler-Sloss stood down as chairwoman in July amid questions over the role played by her late brother, Lord Havers, who was attorney general in the 1980s.
Her replacement Fiona Woolf, the then Lord Mayor of London, resigned in October following a barrage of criticism over her "establishment links", most notably in relation to former home secretary Lord Brittan.
And last week a number of alleged victims of child sexual abuse have said they will withdraw from the inquiry into the issue unless the Government makes major changes to it, including extending the period of time it will cover to further back than 1970.
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