Ciro Santilli is a UK resident. He will register as a "solo trader" (slightly funny legal term) and treat donations that he uses for projects as grants, which pay regular income tax:
The rates are given at: www.gov.uk/income-tax-rates and are as of writing:
- 0 - £12,570 0%
- £12,571 - £50,270: 20%
- £50,271 - to £125,140: 40%
- £125,140: 45%
National insurance is also likely going to be paid: www.gov.uk/self-employed-national-insurance-rates:
- 6% on profits between £12,570 and £50,270
- 2% on profits over £50,270
Fortunately however VAT does not need to be paid.
The amount that will be declared is the same as he grant amount that was requested, e.g. if 100k USD is requested for 1 year, then 100k USD will be pro-rata declared on that year.
Any remaining donations that don't yet meet specific grant goals will be initially treated as cash gifts which pay no tax. If in the future they are used as grant money after further goal amounts are reached, then they will taxed as grants.
Note however that if the donor is UK-based and dies within 7 years of the gift being given, inheritance tax has to be paid on them as per: www.gov.uk/inheritance-tax/gifts, at a maximum of 32% and going to to 0% at 7 years, so let me know from the afterlife.