Without prejudice to existing possibilities for carrying out further audits, where an audit based on internationally accepted audit standards providing reasonable assurance has been conducted by an independent auditor on the financial statements and reports setting out the use of a Union contribution, that audit shall form the basis of the overall assurance, as further specified, where appropriate, in sector-specific rules, provided that there is sufficient evidence of the independence and competence of the auditor. The report of the independent auditor and the related audit documentation shall be made available on request to the European Parliament, the Commission, the Court of Auditors and the audit authorities of Member States.