British Airways and Iberia-parent International Airlines Group (IAG) could fall foul of EU ownership rules in the event of a no-deal Brexit, Europe’s top transport official has confirmed.

EU transport commissioner Violeta Bulc said the risks “have been known since the day the British people voted to exit.

“We have been asking everyone to take it seriously and prepare for the different scenarios.”

EU rules require European carriers be majority owned and controlled in the EU, with non-EU owners’ shares limited to 49%.

Most carriers likely to be affected by Brexit, including easyJet and Ryanair, have provisions to retain 51% EU ownership and EU operating licences by compulsorily buying out non-EU investors.

But IAG chief executive Willie Walsh has dismissed fears of post-Brexit problems as “nonsense”.

IAG is Spanish registered and listed on both the London and Madrid stock exchanges, but its UK stakeholders currently contribute towards a 51% EU holding.

The group, which includes Aer Lingus and Barcelona-based Vueling as well as BA and Iberia, requires a UK-EU deal on Brexit to keep it within the ownership rules.

Bulc told business newspaper the Financial Times: “If there is no deal, I don’t need to point out which side the EU will be on. It’s Spain that we will have in mind.”

An IAG spokesperson said: “All parties have a shared interest in ensuring existing rights continue under new bilateral arrangements.

“We have every confidence the US and UK will sign a deal that is in everyone’s interests.”

The EU has played its part in withholding clarity about the post-Brexit arrangements by refusing to allow the UK Civil Aviation Authority to discuss post-Brexit arrangements with EU regulators in advance of a deal, despite protests from aviation bodies.