Becoming Compliant

Okay, first off this isn't me...but a friend of mine is a freelance contractor and has not paid any tax for the last three years. he is about to start a more settled job and will be going on the payroll and starting to pay tax. what's his best route:
a: reveal all to revenue? (if so what percentage of earnings would he owe them?)
b: sit tight and hope nobody asks questions?

love to have your toughts on this..

The former. Anything else is deliberate and criminal tax fraud. End of story.

Indeed. There is nothing unclear here and ubiquitous has answered the main question. A secondary issue is that in order to find out what he owes he most likely needs to get professional advice in order to prepare and submit appropriate returns.

Well just how compliant was he? Are we talking about a builder here? If so your <expletive deleted> If your "friend" was obliged to charge VAT on goods/ services he provided then your looking at nice big tax bills!!

As a percentage, put it this way it would be the other way round that would make more sense. His income as a percentage of the tax bills!!

Youe "friend" looks for a seriously professional tax firm engage them and your "friend" has a mattress that's about 10 foot off the ground because of money under it!!

Your friend other problem is that Revenue more than likely know the fact that he's not complaint already!!

Go for a top ten firm, 6-10. And hope for the best.