90.—(1) Where an authorised person makes a complaint to the management of the F119[railway organisation] which appointed him or her that—

(a) a safety critical worker has been convicted of an offence under Chapter 2 of Part 10, or

(b) in his or her opinion, a safety critical worker has—

(i) failed to comply with his or her duty under section 87(1),

(ii) failed without reasonable excuse to comply with his or her duty to provide a sample under section 89, or

(iii) contravened subsection (6),

the F119[railway organisation] concerned shall—

(c) in the case of a complaint under paragraph (a), satisfy itself as to the fact of that person's conviction, and if the code of conduct so provides, inquire at an oral disciplinary hearing into the circumstances of that conviction, and

(d) in the case of a complaint under paragraph (b), satisfy itself as to the facts and circumstances of the matter at an oral disciplinary hearing.

(2) Where, in accordance with subsection (1)(c) or (d), a F119[railway organisation] is satisfied that a safety critical worker—

(a) has been convicted of an offence under Chapter 2 of Part 10, or

(b) has—

(i) failed to comply with his or her duty under section 87(1),

(ii) failed without reasonable excuse, to comply with his or her duty to provide a sample under section 89, or

(iii) contravened subsection (6),

it shall decide the course of action to be taken (including dismissal, termination of contract, suspension, demotion, prohibition on working at the undertaking or working at safety critical tasks, or mandatory attendance at counselling) in accordance with the code of conduct.

(3) A safety critical worker who is the subject of a disciplinary hearing under this section may represent himself or herself or be-represented by another person at the hearing.

(4) Where a F119[railway organisation] imposes any sanction against a safety critical worker as a result of a hearing under this section, it shall afford the worker an opportunity, at his or her choice, to appeal to it or to such other person or persons nominated by the undertaking against the sanction.

(5) A person nominated under subsection (4) shall be independent of the undertaking and shall not be a member of its staff or connected to it or be a member of the staff of or connected to another F119[railway organisation].

(6) A safety critical worker shall not take or attempt to take any action with the intention of frustrating disciplinary measures under this section.