Stolen Identity

Hello there, please can you advise on what to do. Someone had used my name and my former address to give to a ticket inspector when they travelled without ticket. Several letters were sent there but I didn't receive any letter because I no longer lives there.
I just received a letter from the court about two years later at my current address to pay a fine of £700 because there's been a single justice procedure which I knew nothing about.

I'm going to appear in court next week to explain that it was not me and someone else had used my details. I thought the inspector should have a way of checking that people are who they say they are.
Please can you advise on what to expect. I'm really nervous. Never been in court before, but cannot pay for what I did not do.

Your advice is much appreciated.