Immanuel College pupils, former students and staff have been raising funds for the family of its popular head of geography who has terminal cancer.

Paul de Naeyer, who joined the Bushey school in 2004, has not been at Immanuel this academic year.

“I spoke to my consultant and we discussed how long left,” said Mr de Naeyer, who is in his late 30s. “She said it was months and that 12 would be a good effort. I am now basically just trying to control the pain by increasing my tablets as and when.”

Current and ex-pupils used the popular ratemyteachers.com website to express their admiration for Mr de Naeyer, who also organised school ski trips. Further tributes were paid on a fundraising site page, where former Immanuel student Joe Hyman wrote that he “really enjoyed the first ski trip you arranged for school. I hope you know how much everyone at Immanuel appreciated you.” Genevieve Schwartz said he was “one of the most inspiring teachers I have ever had”.

The school recently held a “Wear Orange for Paul Day” — orange is the favourite colour of Mr de Naeyer, who is married with two young sons. The day raised £4,000 and a film show will be held next month to generate further cash.

“The generosity and kindness of all at Immanuel has been unimaginable,” Mr de Naeyer said. Paul Abrahams, a close friend and the head of modern languages at the school, said: “We are all thinking of Paul and his family at this difficult time and are doing whatever we can to support them.” More than £18,000 has been raised to date.