Read all the details in the full BMJ Investigation
https://www.bmj.com/content/380/bmj.p329

Private hospitals were paid around £2bn to help the NHS during the first year of the pandemic. Although they carried out millions of outpatient and diagnostic activities, some admitted few inpatients or used most of their beds to treat private patients.

A BMJ investigation has found that, despite a generous contract with the NHS estimated to be worth around £2bn, the private sector was massively underused in many areas of the UK during the pandemic. The investigation found that just 30 of the 200 private hospitals were used to treat patients with covid-19 in April 2020