Or from the Seinfeld episode "The Pool Guy" (Aired November 1995) which had a fictional movie called "Chunnel" -- probably based on the very same channel tunnel.

From Google (AI slop at top of search results): "Chunnel" is not a real movie but a fictional film from the TV show Seinfeld. It is depicted as a disaster movie about an explosion in the Channel Tunnel...

Weird hearing that name now though. Around that time, everybody referred to it as the "Chunnel", but I don't think I've heard it as anything but the "Channel Tunnel" since maybe 2000. I suspect even that usage is now limited to only taking cars on the train from Folkestone. Every time I've travelled on it as a regular passenger from London, it's just been referred to as the Eurostar without any mention of the tunnel at all.