An unsupervised learner driver was arrested after they tested positive for cocaine and cannabis.
Police stopped the vehicle on Woodstock Road in Oxford for having no insurance.
Further checks revealed the driver held a provisional drivers licence and was not being supervised.
Under UK law, when learning to drive a car you must be supervised by a driving instructor or someone else who meets the rules, for example family or friends above the age of 21.
The vehicle was seized.
TVP Roads Policing tweeted: "Driver provided positive drugwipe for cocaine/cannabis and arrested."