Capital Gains Tax - Gifted Property

If you have a signed TR1 but the transferor's ID1 has expired, so the transfer has not yet been submitted to the land registry, when would CGT be due? Is it once the transfer has been registered, completed or signed? Is the transferee responsible for this payment ( not spouse) , or is the transferor responsible for making the payment? What would the situation be if the transferor lived overseas? Thanks in advance!

Hi,
Any capital gain is to be paid by the transferor. This is to be declared within 60 days of the trnafer taking place and not the date the TR1 is registered.
Thank you.