The cost of investigating child sex abuse hit £1 billion last year, a senior officer has revealed, and could treble by 2020.
Simon Bailey, national police lead for child protection and abuse, said the average cost of an investigation is £19,000 and with an increase in allegations, the bill reached £1 billion in 2015.
He said allegations had increased by 80% in three years with 70,000 investigations last year.
The increase is driven by the opportunities provided by the internet with children watching pornography thinking that it is normal, he told The Times (£).
His comments came as Scotland Yard announced that Operation Midland, the police investigation into historical claims of a Westminster VIP paedophile ring, closed after no arrests.
He called on internet companies to restrict access to porn to adults in the same way gamblers must prove their age before making bets online.
In November, Mr Bailey, the chief constable of Norfolk Constabulary, warned that a generation are "living out" what they see.
He told ITV News: "I have had cases whereby 12,13-year-old boys are abusing four, five-year-old girls because what they have seen online they just thought was normal behaviour."
Mr Bailey said he initially believed that an increase in cases was down to more victims coming forward after DJ Jimmy Savile was exposed, but now believes more victims are being abused, both by adults who groom children and peer-on-peer abuse.
More than 20% of prosecutions involve under-18s, including incidents relating to gang abuse and those which start in consensual relationships but which escalate after young couples make a sex tape and one party threatens to release it, Mr Bailey added.