The UK Competition and Markets Authority (CMA) has opened a formal merger inquiry into Irish regional airline CityJet’s plans to wet-lease two Avro RJ85s to International Airlines Group (IAG) Irish carrier Aer Lingus.

CMA launched a formal inquiry Oct. 29, marking an escalation of an initial enforcement order that was issued Oct. 4.

The investigation relates to Dublin-based CityJet’s late-August announcement that it plans to relinquish operating Dublin-London City in its own right and instead fly two Avro RJ85s on behalf of Aer Lingus from Oct. 28. The aircraft will fly in Aer Lingus colors, with the IAG carrier’s service model on board.

“The Competition and Markets Authority (CMA) is considering whether it is or may be the case that this transaction has resulted in the creation of a relevant merger situation under the merger provisions of the Enterprise Act 2002 and, if so, whether the creation of that situation has resulted, or may be expected to result, in a substantial lessening of competition,” CMA said.

The CMA has given interested parties until Nov. 12 to submit comments, with an initial decision planned by Dec. 24.

“CMA cannot guarantee that the decision will be announced on or before this current deadline, as the deadline of a given case may change during the merger assessment process due to different reasons,” the body said.

Victoria Moores victoria.moores@informa.com