As many as three million "ghost" patients registered with GP practices in England should be removed from doctors' lists, latest figures suggest.
As of March 2016, there were just over 57 million patients on GPs' books.
But official census data suggests the correct figure should be about 54 million.
NHS Digital says some of the discrepancy is because patients who have died or left the country have not been removed from GP lists.
NHS England has already announced new rules to find and remove these "ghost" patients.
The potentially crucial bit for long-term ME patients
Patients will be sent letters when they have not seen their GP for five years.
If they fail to respond, a second letter will be sent. And if that is not answered, the patient will be deregistered.
A patient then wanting to get back on a list would have to reapply through the normal process.
The article doesn't say when this will start happening but I can easily imagine some ME patients falling foul of this and being deregistered. So, when you see this letter, respond.