If you HODL and not cash out then I guess when you do cash out you would pay CGT.
You would have at least 20-30 payments into your wallet in a year hypothetically speaking of course, how can they expect someone to declare each of these individually? Surely declaration of total amount at the end of year is reasonable?
Anyway this will infuriate most on this forum but that's not the intention, it is to understand how people think they'll get away without taxation.
Yes, you are only required to fill in your tax return once a year, but you have to keep records of every transaction individually.
My mining is paid in to my account daily, but no I don't have to phone up HMRC every day to tell them, I just collate the data and file it with my tax return every year.
Its about how you record the data - its much easier to make a record yourself at the time, than it is to wait till the end of the year and then have to go through all 20-30 of those payments trying to work out what the historic £ equivalent was at the time.
For the vast majority on here that are likely to only be mining on say 1 GPU just to recoup some of the cost, their mining will be below the £1k threshold and even if they hold it for a long time and cash out its probably going to be below the £12.5k CGT allowance too, particularly if they don't cash it all out at once.
Even for me, I've been mining over 5 years, my mining profits per year have mostly been below the £1k but I'm now sitting on £30k's worth (actually that was a few weeks ago, its probably worth a bit more than that with the sudden increase in BTC), but my plan is to wait way in the future and cash it out at like £10k per year as nice little bonus in years where I don't make any other disposals that would attract CGT.
But, if HMRC get a data dump from an exchange and your name is on there, but you aren't filing a tax return, then the chances increase massively that you are going to get a knock at the door, so its best to keep records and sign up for tax returns than to just sit on it hoping they never find out.