Joshua Robinson was jailed for four years for having sex with two 15-year-old girls and keeping a stash of child pornography in his Singapore apartment

Singaporeans have shared their outrage over the four year prison sentence of an American pedophile which they say may attract foreign sexual predators to their country.

Joshua Robinson was sentenced to four years imprisonment for having sex with two 15-year-old girls and filming it last week.

The 39-year-old mixed martial arts instructor lives in the country but is originally from Herscher, Illinois.

Police found 321 child porn films in his apartment and had made a six-year-old girl watch one which showed him having sex with an adult woman.

On his website he argued sickeningly that girls were in their 'biological prime' from the age of 13 and told how sexual assault victims made for the best partners in bed.

Despite Singapore's notoriously tough corporal punishment system which still includes caning, Robinson was jailed for just four years after striking up a plea deal with prosecutors.

It has sparked outrage among thousands of residents who say the sentence sends the wrong message to foreign sexual predators.

Robinson met the first one on a dating website in September, 2013 and had unprotected sex with her at his apartment, recording the tryst on his phone.

More than 28,000 people have signed a petition calling for him to be given a harsher sentence

He picked up the second girl in June 2015, had sex with her and filmed them having sex too. Two days later, she had a 'mental breakdown' and told her parents who alerted police.

Robinson was arrested and faced dozens of charges including many for child pornography.

When police raided Robinson's apartment they found thousands of illegal porn films, hundreds of which involved children. At the time they said it may have been the largest haul they'd ever found.

But because both of the girls he had sex with were above 14 at the time, Singaporean law considers them able to give consent to have sex with adults. Statutory rape, whereby a child beneath a certain age is deemed too young to give consent, only applies to children under 14.

As a result, he was charged with sexual penetration of a minor over 16 which carries a maximum sentence of 10 years.

Robinson struck up a deal with state prosecutors who offered him a four year sentence in exchange for pleading guilty to nine different charges. They included three counts of sexual penetration of a child under 16, making an obscene film, possession of obscene films and exhibiting an obscene object to a young person.

Robinson struck a deal with prosecutors which means he will spent just four years behind bars

He was jailed last week after a judge accepted the deal, sparking outrage among the local community.

Twenty-eight thousand people have signed an online petition calling for Robinson's sentence to be reviewed. It was launched by a friend of the parents of the six-year-old girl he showed the obscene film to.

'Pedophiles will come from far and wide to take advantage of such an incredibly erroneous measure of justice' its creator, Sarah Woon, said.

Robinson filmed himself having sex with the girls in his high rise apartment in Singapore (above) where police also found hundreds of child porn tapes

'The 6 year old in this traumatic case is a daughter of a close friend and it absolutely breaks my heart and those of all our friends and family,' she added.

The petitioners demanded that he face caning, a form of corporal punishment that is still commonplace in Singapore.

The Attorney General stood by the plea deal on Wednesday. Its chambers issued a statement to say he hadn't been jailed for longer because the two girls he had sex with gave consent and it shouldn't therefore be considered sexual assault.

'Both these victims had consented to the sexual acts. Therefore, the offences of rape and outrage of modesty were not committed. By the same token, these were not cases of “sexual assault”' it read.

They added that the plea deal was struck out of consideration for the girls who they did not want to traumatize by asking them to appear as trial witnesses.

'The sentences imposed in this case were broadly in line with relevant sentencing precedents.

'In light of the sentencing position which the Prosecution had conveyed to Robinson and the fact that his subsequent plea of guilt had spared the victims from the ordeal of a trial, the Public Prosecutor will not be appealing against the sentence,' it concluded.