Gifts out of surplus income

I have a number of NS&I index linked savings certificates. I wish to start making gifts out surplus income to my son. If I withdrew the amount of interest and index linking at maturity could this be classed as surplus income?

Hi,
You can see guidance here:
IHTM14250 - Lifetime transfers: conditions for normal out of income exemption: out of income
Alternatively, you can contact our Inheritance Tax team for advice.
Inheritance Tax: general enquiries
Thank you.