The Counsel to the Inquiry (CTI) is the barrister who provides legal advice to the Undercover Policing Inquiry. It is a statutory position, held by a lead barrister, who is in turn supported by a sizeable team of junior counsel.

The Counsel team are
- Lead Counsel: David Barr KC – Chambers: Temple Garden
- Senior Counsel: Rebecca Hummerstone – Chambers: 2 Hare Court
- 1st Junior Counsel: Emma Gargitter - Chambers: Red Lion
A key role is the questioning of witnesses, which under the Inquiry Rules is restricted to Counsel to the Inquiry unless explicit permission is otherwise given by the Inquiry Chair.
To date, the Chair, Sir John Mitting, has set out specific criteria when counsel to core participants will be permitted to ask questions (for details see under Cross-Examination).
Barr, Hummerstone and one of the junior counsel, Harry Warner, have all questioned witnesses in Tranche 1. In Tranche 2 questioning was done by Barr, Daisy Monahan (187 Chambers), Emma Gargitter, John Warrington (5 St Andrew’s Hill), Aphra Bruce Jones (Lamb Building) and Rachel Naylor (Red Lion Chambers).