Articles like this
https://www.kwik-fit.com/blog/drivers-risk-mot-failure-if-tyre-pressure-monitoring-systems-go-unserviced
When this was announced, if the car displayed a TPMS fault warning light on the dashboard, this would be marked as a minor defect. Defects that fell under this category would be considered to have no significant effect on the safety of the car or impact on the environment. They would be suggested to be repaired as soon as possible, but would not lead to an MOT failure.
Then, in June 2019, following the release of the government’s MOT inspection manual, TPMS malfunction changed from defect category to major. A major defect category is considered to affect the vehicle’s safety, put other road users at risk, or have an impact on the environment. This meant that the Tyre Pressure Monitoring System legislation had come full circle, and it once again can result in an MOT failure.
exeterjeep's post in Old topic but new query re TPMS was marked as the answer