Thanks for the feedback...the situation is that shes going to have to face the fact and pay excess taxes and NI... shes hasn't been claiming benefits, shes has student loans to pay.... if the money isn't available what are her options and how would it effect her.
If she went to prison how long?
Or she registered for say last 2 years, and maybe been living abroad for a couple maybe...
It's not exactly ethical but shes a hard working girl and things haven't gone her way, stupid not to pay taxes obviously but i sure plenty of people out there have done worse!!
You should both sit down together and spend the next day or two looking at the different scenarios under which she needs to make contact with HMRC and register her earnings.
You need to devise a plan of action BEFORE you contact HMRC. Yes, it'll take a day or two, but in the grand context of over five years of having not registered, those two days are almost an irrelevance.
Firstly - she will NOT be given a custodial sentence. If she has been self employed for 5 years, and this is her first offence, they will be lenient and fine her the appropriate amount of tax, plus interest, plus fines for not registering. A suspended sentence seems to be the option that most courts take these days. Again, I am assuming that this is her first offence.
The difficulty is if she has claimed either Tax Credits or Benefits in the last five years, whilst also working. I'm sure you're aware of the media and Gov't current hot topic - benefit 'scroungers'. She needs to be absolutely sure that she hasn't received any benefits or tax credits at her declared income levels, which are, of course, not 'correct', since she has been earning for the last 5 years.
If she registers with HMRC now as having been self-employed for the last 5 years there will be considerable demands for her to pay back what's owed. Remember that interest will accrue on the outstanding amounts. They will NOT be interested in any hardship that comes to your GF as a result of not having paid tax and NI on her income for the last 5 years. In the immortal words of Ray Liotta,
"F**k you, pay me".
The two of you need to sit down together and work out exactly what she has earned in the last 5 years, work out the total tax and NI, and then you can pretty much double that figure, to include fines and interest.