Check the fuel cut off switch mate,sounds that way to me,could have easily activated if something heavy knocked into it on the roundabout,but it's not unheard of to activate from nothing.if it's gone off,you'll be able to push it back down and the car should then be fine.otherwise it could be pretty much anything really,see if you can hear the fuel pump kick in when you put the ignition to position 2,should sound like a deep buzz for about two seconds.