You asked
I would like some data relating to young people under the age of 18 who have been convicted of murder.
We said
Thank you for your enquiry.
We do not hold information on young offenders convicted of murder. Statistics relating to convictions are primarily collected by the Ministry of Justice, and they may be able to provide further assistance. They can be contacted at the following email address: statistics.enquiries@justice.gov.uk.
The following article on homicide, using data provided by the Home Office, may be of interest to you: https://www.ons.gov.uk/peoplepopulationandcommunity/crimeandjustice/articles/homicideinenglandandwales/yearendingmarch2018
Table 21 of the appendix tables released with the article contains information relating to the age of suspects convicted of homicide taken from the Home Office Homicide Index: https://www.ons.gov.uk/peoplepopulationandcommunity/crimeandjustice/datasets/appendixtableshomicideinenglandandwales