I boarded a London Bus with an Oyster Card that had insufficient credit for the journey. I had used it twice previously during the day and was unaware that the credit was running low.

However the Revenue Inspector simply asked to see the card, told me that there was insufficient credit and asked for my details. She did not confiscate the card, issue an intention to prosecute notice, or even a fixed penalty, nor was i advised of any rights to appeal.

She did however say that TFL would write to me. So now what? Everything i've read on this subject suggests that Revenue Inspectors are supposed to either issue a penalty fare or advise you of their intention to prosecute.