stalling when coming up to a stoplight

I own a Ford Mondeo ST 220 (petrol). When approaching a set of traffic lights following a long-ish drive the car cut out unexpectedly. It started back up with no problem at all but there was clear loss of power and loss of light display on the dashboard. The problem occurred with no prior warning or having any previous problem with the car. Since it has a clear lack of power and 6 hours since last being run the problem still remains but has improved slightly. The car was filled with oil and fluids only a couple of days ago.