Newborn circ reached a peak of about 25% in the UK just before WWII. After the war several prominent paediatricians and other doctors emphasized that it was unnecessary and the foreskin is functional. When the NHS started up in July 1948, it prioritized procedures by need and routine circumcision fell to the bottom of the heap. A few families still had their sons circumcised privately, but even that fell off by the mid-1950s. The infant circ rate in Britain has been under 1% since then. I have heard several guys in the UK say that they associate circumcision with older guys - which makes sense, because the rate moves only in one direction as a cohort population ages. (A greater percentage of those born in 1950 will be circumcised by age 80 than by age 30.)
Australia took a while longer to coordinate its universal Medicare system, which now does not encourage newborn circumcision or see any national health benefit in it. New Zealand, more closely aligned medically with the UK, went from the highest circ rate in the world in the 1940s to effectively 0 by 1970. A comprehensive book about New Zealand's experience with circumcision is coming out next year.