Horrid Henry fans on alert! Imagine being Francesca Simon and coming up with all the amazing characters in her books, from Perfect Peter and Rude Ralph to the little horror that is Horrid Henry himself. And just imagine reading about your own character in a Horrid Henry adventure, such as Horrid Henry's Monster Movie, and seeing him or her brought to life by Horrid Henry illustrator Tony Ross.

That's the brilliant prize on offer to one lucky winner. All you need to do is think up a great character for the next Horrid Henry book – it could be a girl or a boy and they could be nice or naughty, it's completely up to you!

Describe the character in 50 words or fewer – think about what they look like, how they behave and what their key characteristics are. These descriptions of Horrid Henry's classmates might help inspire you.

Francesca Simon will help to judge the entries and will pick her favourite. She will then write the winner's character into the next Horrid Henry book, due to be published in 2013, and the winner will also receive a drawing of their character as imagined by Horrid Henry illustrator Tony Ross.

How to enter

Email your 50-word description, with "Horrid Henry" in the subject line, to childrens.books@theguardian.com by 23.59 pm on July 16 2012. Please write your description in the body of the email – please DO NOT send it as an attachment.

The email must contain your name, age, address and contact telephone number.

The competition is open to children aged 6-16.

Your email must also include the name, contact telephone number and email address of your parent or guardian. If you are under 12 years of age you must ask your parent or guardian to enter the competition on your behalf. Please read the full terms and conditions below.

Good luck!

Competition terms and conditions

By participating in the "Horrid Henry character" promotion (the "Competition"), you fully agree and accept the "Horrid Henry character" promotion Terms and Conditions (the "Terms and Conditions") set out below (as amended from time to time). These Terms and Conditions should be read in conjunction with information appearing in the online and print newspaper editions relating to the Competition. To the extent there is any inconsistency, these Terms and Conditions shall prevail.

1. The Competition is open to children between 6 and 16 years of age, excluding children of employees or agents of Guardian News & Media Limited ("GNM"), or Orion Books, or their group companies or their family members, of anyone else connected with the Competition. We reserve the right to ask for proof of age of entrants to the Competition.

2. To enter the Competition you must ask your parent or guardian to enter the Competition on your behalf. Your parent or guardian must submit your entry via email to childrens.books@theguardian.com which must consist of, or include, i) "Horrid Henry" in the subject line, ii) your contact details including your physical address and iii) your character description (set out in the email, not as an attachment) of up to 50 words.

3. Please check that your parent or guardian agrees that you may enter the Competition based on these Terms and Conditions.

4. No purchase is necessary in order to enter the Competition.

5. To enter the Competition, entrants must have access to a computer and access to the internet.

6. If you have any questions about how to enter the Competition, please email us at childrens.books@theguardian.com with "Horrid Henry question" in the subject line.

7. Submitting an entry to the Competition is confirmation of acceptance of these terms and conditions.

8. Only one entry is permitted per person. Entries on behalf of another person (except as made by a parent or guardian in accordance with clause 2 above) will not be accepted and joint entries are not allowed.

9. Entry to the Competition opens at midday on 23 May 2012.

10. The closing date and time of the Competition is 23.59 pm on July 16 2012. Entries received after the closing date and time will not be included in the prize draw.

11. There will be one prize consisting of the character being written into a Horrid Henry book by Francesca Simon, in the manner of her choosing, and a drawing of the character by Tony Ross supplied to the winner.

12. One winner will be selected from all entries received by an independent judge or a panel of judges with at least one of them being independent from GNM. Entries will be judged on the following criteria: imagination, humour and writing talent. Full names of the judge(s) will be made available on request. The judge(s) decision will be final, and no correspondence will be entered into.

13. The winner will be notified by email within 28 days of the closing date. If the winner and his or her parent cannot be reached or fail to acknowledge such notification within 7 days of the sending of the notification email, and the prize is therefore unclaimed, GNM will select a new winner of the prize on the same criteria and basis as in clause 12 (and the same acceptance period will apply). If a winner rejects his or her prize, then the winner's prize will be forfeited and GNM shall be entitled to select another winner.

14. The winning character, and the details of the winner, will be published on www.theguardian.com/childrensbooks.

15. GNM requires the consent in writing (which may include email) of the parent or guardian of the winner in order to publish the winner's name, age and town or city of residence on theguardian.com, and to participation of the entrant in promotional activity including the use of his or her photograph in connection with publicity about the prize. If GNM does not receive such written consent from the parent or guardian of the winner then it may award the prize to another entry.

16. GNM will send the prize to the winner after publication of the new book in which the winning character appears.

17. The prize is non-exchangeable, non-transferable, and is not redeemable for cash or other prizes.

18. GNM reserves the right to change the prize at its discretion to an alternative of similar or higher value.

19. Entries must be the entrant's own original work and must not infringe any third party's intellectual property, moral or other rights. Entrant's must not have not entered into any agreements with third parties that effect GNM's rights to conduct the competition and publish the entry.

20. By participating in this Competition and submitting an entry, the entrant hereby warrants that he/she owns all rights in such material. You also grant GNM a royalty-free, perpetual, exclusive licence to use and reproduce each entered story without restriction in any and all media, including for the purposes of the Competition, for commercial use, for publication on any websites and Facebook pages of GNM and its related companies, and for use in the promotional and advertising materials of GNM and its related companies. GNM will not be required to pay any additional consideration or seek your permission in connection with any use or exploitation of the story and shall be entitled to sublicence the use of the story. By entering this Competition you also, where possible under law, waive any and all moral rights that you may enjoy in connection with the story. The entrant agrees to take all necessary action and sign all necessary documentation to give effect to this section.

21. GNM take no responsibility for entries that are lost, delayed, misdirected or incomplete or cannot be delivered or entered for any technical or other reason. Proof of delivery of entry is not proof of receipt.

22. Nothing in these terms and conditions shall exclude liability for death, personal injury or fraud, as a result of negligence.

23. By entering the Competition entrants agree that their personal data submitted as part of the Competition entry process will be stored and processed on behalf of the GNM as data controller in accordance with applicable data protection laws. Entrants agree that such data may be used to contact the winners of the promotion and for publicity purposes as stated above and to provide winners' names to third parties on requests, and in accordance with any other consents given in connection with the Competition. A request to access, update or correct any information should be directed to the GNM at the address set out below.

24. GNM reserves the right at any time and from time to time to modify or discontinue, temporarily or permanently, this Competition with or without prior notice due to reasons outside its control (including, without limitation, in the case of anticipated, suspected or actual fraud). The decision of GNM in all matters under its control is final and binding including any matters not covered above and no correspondence will be entered into.

25. GNM may, in its reasonable discretion, disqualify any entrant whose conduct is contrary to the spirit or word of these Terms and Conditions.
26. GNM shall not be liable for any failure to comply with its obligations where the failure is caused by something outside its reasonable control. Such circumstances shall include, but not be limited to, weather conditions, fire, flood, hurricane, strike, industrial dispute, war, hostilities, political unrest, riots, civil commotion, accidents, supervening legislation or any other circumstances amounting to force majeure.

27. Details of the winners can be obtained by sending a stamped addressed envelope to the following address: The Horrid Henry Competition, Children's book site, Guardian News & Media Limited, Kings Place, 90 York Way, London N1 9GU.
28. The promoter of the Competition is GNM whose address is Kings Place, 90 York Way, London N1 9GU.
29. The Competition and these Terms and Conditions will be governed by and interpreted according to English law and the English courts shall have exclusive jurisdiction to deal with any disputes arising in connection with it.