Airport operator BAA appears poised to take legal action against EasyJet and Ryanair over the withholding of landing fees.

EasyJet informed BAA on Tuesday that it would withhold part of an increase in charges at Gatwick pending the outcome of legal proceedings.

The carrier is seeking a judicial review of a 21% increase in charges at Gatwick that came into force on April 1 after being signed off by the Civil Aviation Authority.

EasyJet chief executive Andy Harrison said: “We are determined to address a regulatory decision that we consider to be unlawful and damaging.”

He said EasyJet would keep the unpaid money in a separate account pending the outcome of a hearing that could be months away.

Ryanair issued a statement saying it would also withhold payment of a 7% increase in charges at Stansted and likewise threatened to seek a judicial review.

But in a statement, BAA said: “We will continue to charge in accordance with the CAA’s decision. We have reminded Ryanair of its obligations under the airport’s conditions of use. BAA will take action as it deems appropriate to recover any underpayment.”

In theory, BAA could seek legal powers to impound aircraft.