I can see where the confusion may have arisen regarding the assertion that there can only be one PI per institution.
According to UK HRA NRES REC SOPs – Version 5.1 March 2012, section 4.7 states:- " There should only be one Principal Investigator at each site".

However later sections of the SOP make it clear that if the two clinical teams are working independently of each other, then the guidance says that the individual teams may be separately identified as research sites and have a PI each. What you described seems like this.

Section 4.15 "where the research is to be conducted in two or more entirely discrete operating units within the same NHS organisation, these units may be separately identified as research sites. Each site should have its own Principal Investigator who is accountable for the whole research team. There should be no dual accountability or overlap between research teams".

Also for GPs, section 4.16:- "In some cases, two or more independent practices may be conducting the research within the same health care centre. These practices should normally be identified as separate research sites".


I hope that helps.