I know jackg has given you some good advice, but this might help your friend too.
The tricky issue may well be if your friend will be paying Income Tax or Capital Gains Tax - have a look at this …
https://www.gov.uk/hmrc-internal-manuals/cryptoassets-manual/crypto20250Quote - “ Only in exceptional circumstances would HMRC expect individuals to buy and sell exchange tokens with such frequency, level of organisation and sophistication that the activity amounts to a financial trade in itself. If the taxpayer’s activity is considered to be trading then Income Tax will take priority over Capital Gains Tax and will apply to profits (or losses).”
It may well be if your friend is trading with this “frequency”, it may well be considered that it will fall under Income Tax
Below examples are taken from…
https://koinly.io/guides/hmrc-cryptocurrency-tax-guide/Crypto Capital Gains Tax rates UKUnlike many other countries, the UK doesn't have a short-term and long-term Capital Gains Tax rate. All capital gains are taxed under the same rates. The amount of Capital Gains Tax you'll pay depends on how much you earn.
Here are the 2020-21 rates
Tax rate Taxable income
10% Basic Rate Income Band (up to £50,270)
20% Higher Rate Income Band (up to £150,000)
20% Additional Rate Income Band (more than £150,000)
So as you can see, you'll pay either 10% or 20% tax on any crypto gains, depending on what band you fall under.
If you earned less than £50,270 in 2021 - you'll pay 10% on crypto gains.
If you earned more than £50,279 in 2021 - you'll pay 20% on crypto gains.
How much tax will you pay on crypto income?To figure out how much tax you'll pay on crypto income, you need to first know the crypto Income Tax rates. These are the same Income Tax Bands for your regular income. For 2021 - 2022, the Income Tax Bands in the UK are as follows:
Tax rate Taxable income Band
0% Up to £12,570 Personal allowance
20% £12,571 - £50,270 Basic rate
40% £50,271 - £150,000 Higher rate
45% £150,000+ Additional rate
Hopefully you can see that there’s a big difference with the tax rates , ie , Income Tax and Capital Gains Tax !!
It would be worth having a chat with an accountant who’s had experience with crypto clients. These may be hard to find, but most accountants will offer you a free initial consultation- even by phone or zoom. Don’t be afraid to talk to a few different accountants
Some pretty good references
https://www.coindesk.com/learn/uk-crypto-tax-guide-2022/https://koinly.io/guides/hmrc-cryptocurrency-tax-guide/