Full definition
Principal contractor is defined as: The principal contractor is the party legally responsible under CDM 2015 for planning, managing and monitoring the construction phase of a project involving more than one contractor.
The Construction (Design and Management) Regulations 2015 make the principal contractor accountable for site safety, coordination between contractors and communication with the client and principal designer.
Practically, the principal contractor holds the evidence pack for every subcontractor on site: current insurance, competence records, RAMS and site-specific inductions.