I was very late for my train on Friday, and couldn't find my ticket in my bag so used an oyster card to get through the barriers at Liverpool Street (I had bought it with cash a few days earlier). I showed my ticket to the inspector on the train and must have left it on the table as I could not find it when I was trying to exit the barriers. When the ticket inspector came over I explained that I must have left my ticket on the train. He asked how I got through the barrier and in an attempt to look innocent I said with my ticket- he then took my oyster card but could not find the machine to check it. He then gave me a penalty fare which I paid on the spot. Before this though he called someone and gave them my ID number and my oyster card number. Will this penalty fare be the end of it or will they look into it further and issue me a summons as I used my oyster card at the station? I really cannot afford to have a criminal conviction and am so worried. Please help!!