The government has reformed GCSEs to be more rigorous and to match expectations in countries with high performing education systems. As part of this reform process, a number of GCSE subjects are being withdrawn.
Ofqual, the independent qualifications regulator, has published a list of legacy GCSEs, AS and A levels and the date of the last available opportunity to undertake examinations in each subject. This also sets out the reason for withdrawal where the legacy qualifications are not being replaced as part of the reforms.
The list can be found here: https://www.gov.uk/guidance/timings-for-the-withdrawal-of-legacy-gcses-as-and-a-levels.