• To compare the effectiveness of 3 doses of Dysport (5, 10 or 15 Units/Kg/hip) in the management of chronic bilateral hip pain due to cerebral palsy in children/young people.
  
• The primary endpoint will be the change in score in the Paediatric Pain Profile. [ Time Frame: From baseline to the week 4 assessment ]
  

• To compare the effectiveness of 3 doses of Dysport (5, 10 or 15 Units/Kg/hip) in the management of hip pain as assessed by the change in the score of the Paediatric Pain Profile at all other assessment time points. [ Time Frame: Weeks 12, 16 and 20 ]
  
• To compare the effect of the different doses of Dysport on sleep pattern and quality as assessed using a sleep diary and sleep questionnaire at all assessment time points. [ Time Frame: Weeks 4, 12, 16 and 20 ]
  
• To compare the effect of the different doses of Dysport on oral analgesia intake for hip pain at all assessment time points. [ Time Frame: Weeks 4, 12, 16 and 20 ]
  

Inclusion Criteria:

• Male or female aged between 4 and 16 years (inclusive).
• Diagnosis of cerebral palsy.
• Presence of clinical bilateral hip pain (of at least 6 months duration) due to cerebral palsy as defined by the child/young person and/or parents.
• Paediatric Pain Profile score of 25 or greater.

Exclusion Criteria:

• Prior treatment with Botulinum toxin (any serotype, administered anywhere in the body) within 4 months prior to Screening.
• Planned or anticipated requirement for surgery during the study period.
• History of hypersensitivity to the investigational drug or any of its excipients.
• Likely to require treatment during the study with drugs that are not permitted by the study protocol or that in the opinion of the Investigator may interfere with the evaluation of the efficacy or safety of the study medication.