European manufacturing giant Airbus has cancelled a contract for 50 new A321neo planes with Qatar Airways as a dispute over paint degradation between the two deepens.

The Middle East carrier issued legal proceedings against Airbus at the High Court in London in December in a dispute over the grounding of its fleet of A350 planes.

The airline took 21 aircraft out of operation last year, arguing paint on the fuselage was “degrading at an accelerated rate” and creating a safety concern.

Airbus countered, blaming the airline for an “ongoing mischaracterisation of non-structural surface degradation”.

The manufacturer said the surface paint-related findings have been thoroughly assessed by its own team and confirmed by the European Aviation Safety Agency as having “no airworthiness impact” on the A350.

The dispute is ongoing, with a hearing due in April.

A statement over the weekend from Qatar Airways said: “We continue to strongly believe that Airbus must undertake a thorough investigation of this condition to conclusively establish its full root cause in order to establish whether any proposed repair solution will rectify the underlying condition and ensure no risk to the continued airworthiness of the aircraft.”

With regard to the cancellation of the separate A321neo contract, the carrier said it was “adhering to all of our obligations under all applicable contracts”.

A statement continued: “It is therefore a matter of considerable regret and frustration that Airbus has taken the apparent decision to expand and escalate this dispute.

“Qatar Airways remains prepared to help with the root cause analysis however it can.

“In the meantime, we will continue to robustly defend our position in the legal proceedings.”

The A321neo deal was reportedly worth US$6.35 billion when it was finalised in late 2017.

A brief statement from Airbus explained: “We confirm we did terminate the contract for 50 A321s with Qatar Airways in accordance with our rights.”