There is a safe website (D & CH ) where drivers and passengers meet for journeys. You have to register, then you can meet a driver, who charges a small fee. http://www.mitfahrgelegenheit.ch/ http://www.mitfahrgelegenheit.de/
The search function is a bit tedious, and it looks like more journeys are offered on Saturdays.
You will probably have to loook for Zurich to Köln/Dortmund and then at least another leg to London.
I heard there was a similar site for France, but I don't know it.