It cited fuel costs and congestion charges as its main reasons for choosing the Prius, which can run solely on its electric motor up to speeds of around 30mph.
The green credentials of the hybrid also fit the companies environmental policy and aspirations.
A new 'plug in' version of the Prius was due to be unveiled at the Frankfurt Motor Show.
You can read more about the Prius spec and fuel economy on Honest John's motoring pages.
photo credit: autoviva