"When they change their name, they effectively go under the radar of all the authorities - they can obtain a new passport, they can obtain a new driving licence and essentially they can erase their past.
"The onus is on them to inform police, but they are often manipulative by nature. If a sexual offender is on the sex offender register, there must be a system where it's not just reliant on that offender to tell the truth."
The Safeguarding Alliance asked the Disclosure and Baring Service (DBS) how they guard against this. They replied: "The DBS does not undertake any background checks regarding applicants changing their name by deed poll."
the Safeguarding Alliance also asked police forces, in addition to this figure, how many sex offenders have gone missing. Only 16 police forces provided data, but it amounted to 913 offenders.
It's thought many of these have changed their names and chosen not to tell the police.
The Safeguarding Alliance has now launched a parliamentary petition to "revoke the right of registered sex offenders to change their name by deed poll".
news.sky.com/story/more-than-900-sex-offenders-disappear-from-police-radar-with-many-changing-their-names-and-not-telling-officers-12036341