$ cat works.json | reproject --from=EPSG:27700 --to=EPSG:4326 --sr
[...]
Error: spatialreference.org responded with HTTP 301 when looking up "EPSG:27700".
The 301 redirect to https returned for the http request throws an error.
The basic answer of switching the URL to https does not work because the http fetcher included only appears to support http.
Thanks for this package :)