British feature film registrations compared with the quota
Registration was established under the Cinematograph Films Acts to ascertain conformity with the exhibitors' screen quota, which required cinemas to devote a specified proportion of screen time to British productions. A corresponding quota for renters (distributors) had kept pace with that for exhibitors from 1935 and was actually higher for the year from October 1947. However, it was abolished in October 1948, whent he exhibitors' quota shot up from 25 per cent to 45 per cent.
As the chart shows, the proportion of all films registered as British (the dark blue line) in the years from the end of the Second World War until the exhibitors' quota was also abolished was never high enough to match the level of the quota (the lighter blue bars).
Measuring one proportion against another is not the whole story, as it would be necessary to release only enough British films for cinemas to satisfy requirements.