Suppose a close foreign friend entrusts a UK resident with a large sum of money to safely invest in high interest savings accounts in the UK, given that the interest rates in their country of origin is low. They are not UK resident.
Bank accounts are then opened up in the UK resident's name with the box for gross interest payments (and possibly a R85 form) checked. Every month, the interest is collected and sent to a UK bank account of the non-UK resident.
The person managing the money is not expecting any regular payment for their service. An occasional gift of gratitude is possible.
Is this setup entirely tax free? Assume all the necessary documentation can be obtained, e.g. letters saying that "I am allowing X to manage my money, and they do so entirely out of goodwill."