Let's say my brother acts as guarantor for my mortgage, so that I can buy a bigger house than before. He does not put his name on the house deeds, and he does not contribute to mortgage payments, I can still afford these on my own. I then make ~£9000 a year profit in renting out 3 of the rooms, and in 5 years, the house increases in value by £30,000.
My brother then wants to buy a house. As a thank you for putting his name on my mortgage and helping me, I want to give him £30,000, to help him with his deposit.
Would the law see this as a gift (tax free), or would they see it as us trying to avoid income tax that we would have to pay, if for example, we decided to pay my brother in rental income from my house instead?