A man who admitted planning to kidnap, torture and eat at least one child using a sound-proofed dungeon he built in his Massachusetts home has been sentenced to nearly 27 years in U.S. prison.

Forty-year old Geoffrey Portway, a British citizen, received the sentence in federal court on Tuesday (September 17) after pleading guilty to charges related to child pornography and plotting a kidnapping and violent crime.

Prosecutors say last year federal agents discovered the dungeon, a child-size homemade coffin, and butcher kits in the basement of Portway's Worcester home. Also there: evidence of more than 4,500 exchanges of child pornography on his computer.

Portway admitted in a plea agreement to having had online chats with numerous people about "a mutual interest in abducting, raping, murdering, and eating children."

Portway's attorney said his client was "sick" and should be punished, but added that he never intended to carry out any plans to harm children.

Portway will be deported to the UK after he completes his prison term.