Parents have been informed that a group of secondary school pupils have been taking class A and B drugs.

A letter from Twyford High School executive headteacher Alice Hudson and associate headteacher Karen Barrie, which revealed staff had been made aware of concerns over drug use outside school by some sixth form students, was sent home on Wednesday last week.

Officials at the Church of England school in Twyford Crescent, Acton, had investigated claims and identified individuals who had attended clubs and raves, some in unregulated premises, over the course of the past year, where class A drugs were commonly used.

Enquiries showed the youngsters in question have mainly been using the tranquilliser ketamine, as well as MDMA, better known as ecstasy, which are both illegal. The main dealer is not a pupil at the school.

Twyford High has a zero-tolerance policy on drugs and although the actions took place off the grounds, parents of those involved have been individually contacted and the information passed to the police.

One student has been recommended for permanent exclusion.

Ms Hudson said: “The prevalence and availability of drugs to young people is a concern to all parents as well as to schools. I am simply relieved that we were able to deal with this situation as rapidly and effectively as we did. Twyford is very proud to have a zero-tolerance approach to drugs and substance abuse and works very closely with parents to ensure that its values and standards are sustained.”

The headteacher said all parents were immediately told about the incident so informed and open conversations could take place at home.

In the letter sent to parents, it mentioned that students were aware that drug offences in or around school may lead to exclusion and that they are responsible for upholding the school’s code of conduct.

Staff will hold appropriate assemblies and cover the legalities and risks of social drugs during tutor time.