A former Royal Navy chief petty officer has been jailed for two years after using the internet to try to have sex with a child.
Jeremy Pepper, of Hove, East Sussex, sent a series of e-mails to someone he thought would help him find a girl aged between 11 and 14 years old.
But the weapons expert was discussing his demands with UK and US undercover police posing as paedophile contacts.
Pepper, 31, pleaded guilty to the charges at Middlesex Crown Court.
The court had heard how Pepper logged on in June 2001 to what he thought was a US-based child porn website.
However, the site had been set up by the FBI in a bid to catch paedophiles.
Pepper, at first posing as a 26-year-old woman, began exchanging e-mails with an undercover officer, the court heard.
He told the officer he was interested in "child sex tourism" with a girl "11-14ish" and that he was getting "desperate" and "very frustrated" at the lack of progress.
An undercover Scotland Yard officer took over contacting him when the FBI decided Pepper would not travel to the US.
In February 2003, Pepper's patience ran out and he cut off contact with the undercover officer.
When he was arrested soon after, police found more than 400 images of underage girls on his computer.
Jailing Pepper, Judge Simon Smith told him: "What you took part in was an area...in which children go through extreme degradation."
He said a jail sentence was not only to punish him for what he had done, but was also to "show others the danger of getting involved in this kind of activity".
Pepper was ordered to register as a sex offender for 10 years, banned for a similar period from using the internet to contact strangers and prohibited from working with children.