Tax on repayment of loan for ex-wife's home

As part of a divorce settlement 10 years ago I loaned my ex-wife a lump sum to help her purchase her new home the loan being secured by a charge on the property. The amount when repaid to me will be a % of the new value. What is the tax treatment of the gain in value?

Hi,
Provided the lump sum was in pounds sterling, the sum you receive, minus the original lump sum will be taxable as interest and not capital gains.
Thank you.