Not sure where you are getting that from and you seem to be confusing 1938 (
Rex vs Bourne) with the 1967 (Abortion Act).
Broadly the history is:
-- Abortion was illegal under an act from 1861 unless the woman's life was in danger.
-- In 1938 it was extended this to allow abortion on the grounds of the woman's mental health.
-- The 1967 act made abortion legal within certain rules (24 weeks, doctor's opinion, etc) but with a broad enough scope that it effectively made abortion fully legal and widely available in the UK.
https://www.bpas.org/get-involved/campaigns/briefings/abortion-law/