Will I need to pay tax on future lump sum?

My ex is staying in the family home and has paid me roughly half my share of it now (180,000). Our Consent Order says that she''ll pay me the other portion (about 150,000) plus simple interest based on the CPI in 10 years time, when the children are both over 21.

I don''t have an interest in the house and the figure in our settlement will only increase by inflation. Let''s say that over 10 years that turns out to be 10%. So the figure she''d pay would be 15,000 more than it is now.

I don''t think this is a capital gain, since the increase in the figure is not due to the increase in the value of a capital asset. But if I recieved £15,000 interest on a savings account over 10 years I would presumably have to pay income tax on that interest.

I''m wondering if my understanding of this is correct, or is the calculation that''s described in the consent order considered to be settled at the eventual figure rather than the original lump sum?

Also, if I do need to pay income tax on this figure, would it count as income in the year that she pays me, or as a smaller income in each of the 10 years leading up to that.

I think I am right in saying that there are certain CGT concessions which can apply in situations like this, but I don''t feel confident enough to be totally aware of the current rules. I''d suggest you ask HMRC for the exact terms.

I don''t think you are entitled to relief from interest on a lump sum as such, though they may be applicable, for example, if you invest in an ISA.

Again I''d check with HMRC but I don''t think I''m wrong here. There is the obvious point that when you finally get your cash, the rules may have changed.

LMM