Paedophile Gary Glitter has been deported from Vietnam. His release follows warnings by child protection charities that the British government is turning a blind eye to the actions of child sex tourists.
Gary Glitter was jailed in Vietnam for child sex abuse
Home Secretary Jacqui Smith has responded to those criticisms by announcing plans to toughen up the law.
What happens when a British national, convicted of a sex offence abroad, returns to the UK?
Where a known sex offender is to be deported to the UK, British authorities are notified and the individual is met and interviewed by police at the port of entry.
He or she is asked about their offending abroad and officers assess whether there is a need to prosecute them in the UK.
After a recent change in the law, UK nationals who commit sex offences against children abroad can be prosecuted in the UK, even if their actions were legal in the country they visited.
Following the interview, officers will pass on any relevant information to the police in the area in which the offender is proposing to live - if indeed he intends to stay in Britain.
There is no automatic requirement for someone to be added to the sex offenders register, but in many cases that will also happen at this stage.
Can an offender be forced to return to the UK?
If the offender is not wanted for a criminal offence in the UK - and so not subject to an extradition warrant - then the government does not have the power, says Julian Weinberg, a criminal lawyer specialising in dealing with sexual offences.
The offender could only be forced to the UK if the country deporting him sends him straight here. In the case of Vietnam there were no direct flights, so Gary Glitter was sent to Thailand.
If Gary Glitter does return to the UK - perhaps to access NHS services - it would be voluntary, said Mr Weinberg.
While he is currently trying to enter Asian countries where he requires a visa - and so can be denied entry - he could enter an EU country unheeded, he added.
How is the offender monitored in the UK?
Anyone convicted of sex offences, whether in Britain or abroad, may be subject to multi-agency public protection arrangements (Mappa).
Introduced in 2001, Mappa can involve police, probation, mental health services, housing and other social services who are collectively responsible for monitoring someone who poses a risk.
There are varying levels of risk.
Those deemed least likely to reoffend are required to register their address with police and notify them if they move or stay elsewhere for more than a few days.
Those whom police and probation officers deem to be a more serious risk, and who need to be intensively monitored, can be ordered to live in supervised accommodation.
At present, registered sex offenders retain their passports, and, visas permitting, are free to travel overseas.
However, from the autumn, they will have to give seven days' notice of any intention to do so.
Can someone be banned from travelling altogether?
Police can apply to the courts to have a Foreign Travel Order (FTO) imposed on an offender.
These can last for up to six months, although the person retains possession of their passport during that period. It can also apply to named countries or to all travel.
In order to obtain an FTO, police must prove that an individual is at risk of re-offending based on evidence from the previous six months.
Where considerable time has elapsed since the offences, or if, for example, someone has been denied any opportunity to reoffend because they have been in prison, proving imminent "intent to cause harm" in this way can be difficult.
If Gary Glitter stays "clean" the courts would have no means of preventing him travelling abroad, says lawyer Julian Weinberg.
What are the criticisms of UK measures?
Children's charity Ecpat UK says there have been five prosecutions for overseas abuse since 1997, compared with more than 65 by US authorities and over 25 by Australia.
It points out that at least 15 British nationals were charged for sexual abuse of children in Thailand alone between 2006 and 2008, with other prosecutions in India, Ghana, Vietnam, Cambodia and Albania.
The home secretary herself has admitted that police do not often apply for FTOs for paedophiles because of the work involved.
The Home Office says five were issued from 2004/5 to 2006/7. This compares with more than 3,000 issued to prevent travel by football hooligans.
What changes are being proposed?
Under new proposals coinciding with Glitter's deportation, the home secretary has said she wants to "toughen up what is already a very tough system" in the UK.
In particular, she wants to make it easier for police to obtain FTOs, by removing the six-month time limit on the evidence they can use.
The maximum length of a ban would also be increased from six months to up to five years, and those affected would have their passports automatically confiscated.
The changes would also mean that all registered sex offenders not subject to a ban would have to give more notice of any plans to travel abroad.