First welcome to the forum, though you probably don't want to be here right now.
Ok, I'll be straight with you; this is somewhat serious. It's not huge in terms of finances but it's repeated evasion over a prolonged period. Let's look at the worst case scenario - you've not paid the correct fare for 312 journeys. (3 journeys a week x 104 weeks). Usually for smaller offences, most of the train companies (Transport for London excepted) are willing to settle out of court for a moderate amount of money. This is serious enough that there is a
possibility that you may not be offered an out of court settlement and the case ends up in court.
IF it goes to court, I would expect you to be fined and also made to pay costs and compensation. This would result in you having a criminal record, but it is my understanding that it will "expire" after a time - there are others here who are more knowledgable than I am about this, and I expect they will be along later today to clarify.
However. Before you panic about that, you need to realise that you actually don't know what their plans are, and that's because they haven't written to you yet. So you cannot assume they will take any particular course of action or what the outcome will be. I assume you gave the inspector your correct details. If so, then you will receive a letter from either the train company, or the company they use for their investigations, some time in the next six months. That letter will explain exactly what they are accusing you of and under what legislation. Once you have that letter, post
all of it here, making sure to redact your personal information and any reference numbers. The forum can then explain your options and advise you as to your best course of action.
For smaller offences, a letter apologising, showing remorse, and asking for an out of court settlement usually gets the job done. It is possible that this will work for you, but we won't know for sure until we see the letter they send you.
In the meantime, there are a couple of things you can do.
1) To prepare you financially, I would suggest that you draw up a spreadsheet listing
every single journey where you have not paid the correct fare. Once you have a complete list, work out the cost of those journeys. Go to the National Rail website (or West Midlands website if you prefer) and look up the
Anytime Single fare for that journey. Don't use return fares, don't use Off-Peak or Advance fares. The total of those fares is the approximate minimum you can expect to pay if you are offered an out of court settlement. Expect costs of a few hundred on top of that to cover their time and resources.
2) If you are eligible for a railcard to help reduce your costs of travel, buy one now, and ideally a paper one so you can show it even if your phone battery goes flat. It shows that you're making an effort towards making sure you pay the correct fare in the future. See
https://www.nationalrail.co.uk/railcards/national-railcards/ or
https://www.railcard.co.uk/ .
A couple of commonly asked questions:
Q- Should you contact the train company to try and speed up the process?
A- No. They will be dealing with a lot of cases, and you will get your turn when they get to it. Contacting them will not achieve anything and may actually cause more confusion about your case.
Q- Am I definitely going to prison/court?
A- No. In the vast majority of cases there are many steps before you end up there, and as long as you cooperate and are honest, it's highly likely (but not guaranteed) that you will avoid ending up in court, let alone going to prison.
Q- Do I get a criminal record from an out of court settlement?
A- No. The matter is handled between you and the train company (or the company they use for their investigations).
Q- What else can I do in the meantime?
A- Not much. Until you get that letter, sit tight and try and get on with your life. Easier said than done, I know, but you really don't have much other choice here.
Q- Anything else?
A- I'm sure it goes without saying that you need to be 100% correct with your fares from now on - if they do give you an out of court settlement this time and you evade again, they are not likely to offer it again.
If you have any other questions in the meantime, please do ask them. Do bear in mind that until that letter arrives, you really do have to sit tight and wait.