Thomas Cook has now issued a formal apology for the incident. “We are sorry that we upset Ms O’Connor,” the airline said in a statement. “It’s clear that we could have handled the situation better.”

The company said it did have an appropriate attire policy, but that this was available in its in-flight magazine – meaning that O’Connor couldn’t have seen it before she boarded the flight.

The policy states that “customers wearing inappropriate attire (including items with offensive slogans or images) will not be permitted to travel unless a change of clothes is possible”.

However, the policy does not go into detail about what kinds of women’s clothing is considered appropriate, leaving room for staff to interpret it however they wish. O’Connor said that a man sitting two rows behind her was wearing a vest top and shorts, but staff did not ask him to cover up.

Airline apologises for threatening to throw woman off flight if she didn’t “cover up”