The landmark conviction of Watford paedophile Barry McCloud came as a result of an international investigation and exhaustive operations by Hertfordshire Constabulary over more than two years.

In the first case of its kind in the county, officers took the unprecedented step of travelling to India to trace the impoverished nine-year-old McCloud abused between 2005 and 2007.

Investigations into child pornography sites by the Paedophile Investigation Unit led to McCloud's arrest in 2007 and the discovery of more than 100 indecent images of children on his computer.

However, his offences abroad were only uncovered thanks to the “gut feeling” of officers analysing the sickening stills.

Detective Constable Greg Smale, one of the officers in the case, explained: “We see thousands and thousands of these images but there was one in particular that didn't feel right. There was a gut feeling, a professional judgement, that it could have been taken by him.”

Investigations into the possibility McCloud was abusing children himself began in May 2008, leading to the further discovery of indecent video footage of a young girl on his camcorder.

When he was re-arrested in 2008, McCloud denied all knowledge of the images and footage but, when officers established a link between himself and the Indian family, it sparked an international investigation.

Hertfordshire Constabulary led operations, involving the Child Exploitation and Online Protection centre, the Serious and Organised Crime Agency, the Crown Prosecution Service and Justice and Care, which resulted in McCloud's conviction.

The latter, an international human rights agency based in India and the UK that works with governments to support victims of exploitation, helped trace the girl.

DC Smale added: “To visit these slums really does take your breath away on a number of fronts – it is the most abject poverty.”

Having found McCloud's victim, then aged ten, officers used special interview techniques to try and limit the psychological impact on her and ensure her testimony would hold up in the UK courts.

Only later, when McCloud was presented with the video footage found on his camera, along with the girl's testimony, did he admit the offences.

Detective Superintendent Andy Joyce said: “He's very, very good at grooming people into thinking he's a law abiding citizen but the evidence shows completely otherwise. There is a far more sinister side to this middle aged man.”

On Friday, December 10, at St Albans Crown Court, McCloud was handed a life term with a tariff of 14 years and told he would serve a minimum of seven years before being considered for release.

Speaking after the sentencing, Senior investigating officer, Detective Superintendent Paul Doran, said: “It has been years in coming to this day – we got the sentence we wanted and have now taken someone considered very dangerous off the streets of Hertfordshire for a long time.”