1. The persons carrying out the internal audit function shall not assume any responsibility for any other function.
2. Notwithstanding paragraph 1, and in particular by respecting the principle of proportionality laid down in paragraphs 3 and 4 of Article 29 of Directive 2009/138/EC, the persons carrying out the internal audit function may also carry out other key functions, where all of the following conditions are met:
(a) this is appropriate with respect to the nature, scale and complexity of the risks inherent in the undertaking's business;
(b) no conflict of interest arises for the persons carrying out the internal audit function;
(c) the costs of maintaining persons for the internal audit function that do not carry out other key functions would impose costs on the undertaking that would be disproportionate with respect to the total administrative expenses.
3. The internal audit function shall include all of the following tasks:
(a) establish, implement and maintain an audit plan
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