Chargeable events certificate

Following my fathers death I have received a chargeable event certificate, do I declare that gain on my late fathers self assessment or via the will trust he has set up?

Hi

Chargeable event gains are subject to income tax. Any gains are treated as forming part of the deceased’s income at the date of their death and should therefore be included in your late fathers self assessment tax return.  
On the paper tax return, this would be SA101 (additional information).  The online tax return has an option on page 2 of 3 "tailor your return".

Thank you