A legal loophole enabling sex offenders to avoid providing police with a full address has been revealed.
Sex offenders who are homeless can be vague about their address
Freed sex offenders, including paedophiles, can provide a location such as "somewhere in the woods" if they are homeless.
It emerged after a convicted sex offender went missing after telling police he was living rough in Kent.
A Home Office spokeswoman said: "It is a fact of life that not all offenders have a permanent address."
However, she added: "Under the Sexual Offences Act 2003 those with no fixed abode must give a location where they can regularly be found.
"They need to be there and checks will be carried out by the police.
"If you breach the conditions of the sex offenders' register you will be prosecuted."
An address is needed in order to make regular checks that a person will not re-offend, as well as to make immediate checks in the event of a crime being committed.
For example, police officers can carry out checks on the homes of known offenders if a child is missing and believed to have been abducted.
The loophole is believed to have existed since the register was established in 2001, although it has never been made public.
The sex offender who went missing after saying he would be living rough in Kent was eventually tracked down in Devon and taken to court, where he received a conditional discharge.