As part of the Joint Audit Programme (JAP) for EEA GMP Inspectorates, EU inspectorates are audited by other competent authorities. It is run under the Heads of Medicines Agencies (HMA) and on behalf of HMA by the GMDP IWG. JAP aims at achieving and maintaining equivalence between Member States' national inspectorates responsible for GMP. It was established in October 2000 and is an important part of the quality system adopted by all GMP inspectorates in the EU.
JAP auditors are senior GMP inspectors, further qualified for auditing inspectorates through specific training. A list of qualified JAP auditors is maintained by the Compliance Group, which is a subgroup of the GMDP IWG. JAP auditors also provide technical advice and support to accession countries before they become EU Member States. Mutual Recognition Agreement and other international partners are invited on a case-by-case basis to join JAP audits of EU Member States inspectorates as observers.
Now the U.K. Medicines and Healthcare products Regulatory Agency has published a MHRA Inspectorate Blog "Who Inspects the Inspectors?" and gives some insight in such an audit. The information dates back to October 2015 when the MHRA was audited under the JAP. The audit was also observed by the U.S. FDA. Their focus was on the JAP process itself rather than the MHRA's systems. This FDA participation was part of the Mutual Reliance Initiative looking to establish equivalence between Europe and US GMPs. The audit also included two on-site MHRA GMP inspections being observed.
Interesting is the statement that the 6 month preparation period and the 5 day audit had "a significant interrogation of the systems". Maybe this helps inspectors to understand that the industry may have the same issue.