The age of criminal responsibility in England & Wales is 10.
https://www.gov.uk/age-of-criminal-responsibility
However, it is illegal for for an adult to buy or try to buy alcohol for a child under 18,
https://www.gov.uk/alcohol-young-people-law
The adults should have been prosecuted IMO, and the police should have been protecting the children.
Anon thinks the system should be turned upside down so that individuals have responsibilities, not rights. Responsibilities are pretty well covered by the 10 Commandments.