A student who planned to become a teacher has been jailed for three years for trying to procure a nine-year-old girl for sex over the internet.
Sadowski will not be placed on the sex offenders' register
Luke Sadowski, 19, admitted attempting to incite another to procure a child under 16 and possessing an imitation gun.
He was sentenced to 18 months for each offence, with the sentences to run consecutively.
Sadowski, from Bishop's Stortford, Hertfordshire, was arrested in an undercover operation following a tip-off from police in the United States, Southwark Crown Court heard.
Under current legislation, he could only receive a maximum of two years for trying to procure a child and will not have to go on the sex offenders' register.
The law is now being changed and anyone charged with a similar offence in a year's time could face a maximum of 14 years.
Lisa Wilding, prosecuting, told the court Sadowski used internet chat rooms in an attempt to find a child victim.
But the website he used was set up by US law enforcement agents to trap paedophiles.
When Sadowski, who has already served 10 months in custody, continued asking to be introduced to a young girl, they alerted Scotland Yard's paedophile unit.
Using the name Ben Smith on the internet, Sadowski was told to get in touch with the site's UK agents, who were in reality members of Scotland Yard's paedophile unit.
Referring to the nine-year-old he thought he was going to meet, he told one officer: "I am not going to mistreat her, not too much, if you know what I mean."
The undercover officers met him at London's Victoria station and took him in a cab equipped with video recording equipment to a hotel where he was arrested.
In addition to the gun, he also had on him a teddy bear and a condom.
These implements were found in Sadowski's home
The court heard Sadowski had set up a memorial site on his computer for murdered schoolgirl Sarah Payne and was going to do one for the Soham schoolgirls.
Sadowski was about to begin a foundation course at Canterbury Christ Church University College, which would have allowed him to pursue a degree in primary school education.
Judge Gordon told Sadowski there were a number of features in the case which "give rise to real serious concern about the danger you may pose to women."
'Fantasy and bravado'
He had read psychiatric and probation reports which also indicated "elements of fantasy and bravado".
Emma Edham, defending, said Sadowski had behaved in a "stupid, frightening and disgusting way", but "it was no more than a boy's stupid experimentation".
NSPCC policy advisor Christine Atkinson said in a statement: "We welcomed the clearer offences and tougher sentences for sex offenders announced in the Queen's Speech last November.
"It is a priority that the proposed legislation is implemented as soon as possible to protect children."
Two weeks before his arrest he had been due to spend a week working at a primary school to gain work experience, but this was cancelled by the school after they were contacted by police.
When his student accommodation was searched police discovered a safe containing leg shackles, handcuffs, an extending police baton, a kitchen knife and a roll of tape, Miss Wilding told the court.
Police video shows the moment a replica handgun was found in Sadowski's waistband
They also found several newspaper articles about paedophiles, child abductions and murders.
Detective Chief Inspector Matthew Sarti, of the Metropolitan Police Paedophile Unit, said: "By conducting this operation we have identified and brought to justice a young man who posed a considerable danger to children.
"The contents of Sadowski's safe show what can only be described as sadistic implements of restraint, apparently assembled within days of his new found freedom and financial liberty at college
"Sadowski intended to study to become a primary school teacher and we can only be grateful that he was caught well in advance of this becoming possible.
"The successful prosecution of Sadowski shows that police are prepared to do all it takes to protect children from those who want to abuse them".