2003 Ford Mondeo intermittent starting problem

Hello everyone.New on this board and after any help possible.I have a problem with my starting.When I try to start my car I wait for the various lights to go out and turn the key to start.Absolutely nothing happens.I try again and it might start.Sometimes I have to go through this procedure several times.I have tried reprogramming the keys,but this will only work a few times.The immobiliser accepts the keys,but it is just dead (I have tried a bump start and it works,so it can't be immobiliser )Sometimes it will start first time and after maybe driving for an hour and switching off and on again it is dead.The glow plug or engine management lights are not coming on ,so I don't think it will have stored a fault.Any help greatly appreciated.Thanks in advance