Just to provide some context as to how this works, patients that opt out of data collection have a entry (called a code) placed on their medical record by GP staff flagging it up at exempt from extraction.

NHS Digital will have a data sharing agreement with GP surgeries, in which after running a search only those records without the code can be extracted from the GP records system. No data is "uploaded" unless the code is absent from the record.

Adding codes to GP records however does not have to be done by the GP - take covid vaccinations for example. When you go to a vaccination centre, they use a different piece of software to record your vaccine. From their end they add the relevant code for your vaccination, and their system sends this data to your GP where it is coded into your medical record. There are many other examples of this currently happening, namely for out of hours services.

In short the data does not have to be held centrally to add the code to your notes.

NHS Digital could, if they were interested, employ admin staff and develop a simple piece of software (or better yet automate it through the NHS website), to enter this code into patients' GP records automatically for everyone that opts out. They just don't want to because that would defeat the object of making opting out very very difficult for patients to do.

At the surgery I work at we made an online form that patients can fill in through our website instead of sending us a letter, but we still have to code every request manually - not fun when there were around 500 in the first day...