I was driving on the motorway, about 10 minutes into the trip while being in 5th and going about 75mph my whole car cut out. The engine stopped, and the electrics also stopped. After trying to resart the engine by turning the ignition about 10 seconds later the engine finally started. I turned off at the next junction and couldnt see anything wrong under the bonnet (not that I would notice if anything was wrong!), and after ringing my dad I went back onto the motorway. About every 5 minutes the electrics cutout, but thankfully the engine did. Any explanations would be cool, ive booked the car in at the garage and hopefully it will all be good again!