Pokemon-mad Lisa Courtney has earned a place in the record books with a memorabilia collection of more than 12,000 items.

Ms Courtney is listed as having the biggest Pokemon collection in the world - 12,113 items - in the new edition of the Guinness World Records Gamer's Edition, published yesterday.

The 21-year-old, from Welwyn Garden City, Hertfordshire, has spent 13 years building up the collection which she said has swelled to more than 13,400 since it was counted by Guinness record-checkers last year and fills most of the house she shares with her mum, Sharon.

"To be in the new Gamer's Edition and to hold a world record for something you feel so passionate about is just an indescribable feeling," she said.

"My family have been incredibly supportive considering the collection takes up the whole house, including my mother's room!

"I've even named the room where my main collection resides Pokemon Centre Europe!"

Ms Courtney began her love affair with Pokemon when she saw a picture of Pikachu in a Nintendo magazine and started collecting even though she had no idea what the characters were.

"My favourite is a plush toy of the character Absol," she said.

"I fell in love with it."

Ms Courtney said she will never get bored of collecting: "There's always something new coming out in Japan. There's so much out there."

Ms Courtney, who is unemployed, is learning Japanese and hopes to one day become a Japanese teacher.

Guinness World Records 2010 Gamer's Edition is the third instalment of the series.