From TARDIS Index File, the free Doctor Who reference.

Deffry Vale High School was a high school located in Deffry Vale, London, England.

It was infiltrated by the Krillitanes and was brought to the attention of Sarah Jane Smith and Mickey Smith separately. The Doctor and Rose Tyler were undercover in this school during the final stages of the Krillitane's plans, thanks to Mickey.

The school was heavily damaged in early 2007 when K-9 destroyed a vat of Krillitane oil. All the Human staff were killed by the Krillitanes, and all the Krillitanes were killed in the explosion. (DW: School Reunion)