Fine airlines if they fail in legal duty to customers, urges Which?

Passengers queue in departures at Heathrow terminal 2. Which? said airlines had legal responsibilities to their customers that are frequently ignored. Photograph: Henry Nicholls/Reuters

Airlines that break the law by not helping customers when flights are delayed or cancelled should be fined, consumer rights groups and online travel agents have said.

In a letter to the prime minister, Rishi Sunak, the consumer rights group Which? and leading online travel agents called for the aviation regulator to be given more powers to act amid flight cancellations.