In the US, we just called these knickers, though I know in the UK that means ladies' underpants. I remember them being really popular about 1969-1970, usually in corduroy, suede, or velvet. Women would wear them with turtlenecks or romantic, puffy-sleeved shirts with big collars, often with vests and sometimes with maxicoats. They paired them with the knee-high "granny boots" popular about the same time that laced up to the knee and had a low, block or flared heel and bumpy toes. Men wore knickers too at the time, also with boots - young, stylish men at least. They were revived in wider wale corduroys and other fabrics for fall 1981; this time, women wore them with dark hose/tights, flat pumps, and prairie blouses or sweaters.

I had a pair around 1974. I wore them with knee-high socks that were tucked under the button closure of the knickers, platform shoes, and a matching short-sleeved turtle neck.