He has also been given a ten-year prevention order that stops him having unsupervised contact with children.
The offence happened nearly two years ago when the little girl spent the night with her friend, David Chamberlain's daughter, at his home in west London.
But what is particularly shocking about the case is that Chamberlain, 43 – who was director of the London Screenwriters' Festival last year – was already a registered sex offender in the US. Yet he was able to come over to Britain and commit a similar offence.
In the States, Megan's Law gives members of the public access to information about convicted sex offenders. (Megan's Law was named after seven-year-old Megan Kanka from New Jersey, who was raped and killed by a known child molester who moved in across the street from the family home.)
In California the Department of Justice has a dedicated website giving details about sex offenders. The entry for David Chamberlain is easy to find. It states that his offence was 'attempted annoy/molest children', and that 'this sex offender has been in violation of registration requirements' since 28 July 2008.
So why was David Chamberlain allowed to come to Britain and molest another child?
According to the UK Border Agency, the responsibility for giving out information about past convictions lies with the country in which an individual lives.
A spokesperson said, 'Passengers travelling to the UK are checked against a range of watch-lists. The onus for flagging an individual's criminal history lies with the police in their home country.
'Our priority is to protect the public and we strongly believe foreign law-breakers should be removed from the UK at the earliest possible opportunity. We will automatically seek to deport any foreign national criminal who has been jailed for a serious offence.'
Would it have made any difference if the UK had adopted Megan's Law too? In the UK, 'Sarah's Law' was proposed after the tragic murder of eight-year-old Sarah Payne by convicted sex offender Roy Whiting ten years ago. This has resulted in the Child Sex Offenders Disclosure Scheme, which is now being rolled out in England and Wales. The scheme allows parents, carers and guardians to formally ask the police to tell them if someone has a record for child sexual offences.
Home Secretary Theresa May said, 'The UK already has one of the strictest systems for managing known sex offenders in the world, and this scheme further enhances our ability to protect children.'
But children won't be fully protected unless countries share information. David Chamberlain should not have been able to commit the same crime again.
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