I live in the UK. Specifically, how do I draft a loan agreement that provides basic safeguards for borrower and lender (very basic safeguards, as we're talking about an intra-family loan and the level of trust is very high), and also satisfies tax requirements so that it doesn't look like the lender is gifting the principal at a non-commercial rate.
The Virgin Money Family Mortgage mentioned on this page appears ideal, but about.com appears to be US-centric and I can find no evidence that Virgin Money actually offers such a product.