If the delay is for five hours or more, passengers are also entitled to a refund of their ticket with a free flight back to the initial point of departure if this is relevant (for example, if a connecting flight has been cancelled).

BBC: NEWS | Business | Q&A: Grounded BA passengers

Ticket buyers would have the right to a refund within 48 hours of purchasing a ticket, even "nonrefundable" ones.

FORBES: Fact and Comment

If you paid for tickets on or before July 22, 2011, for travel beginning on or after July 23, 2011, you may be entitled to a refund of ticket taxes already paid.

FORBES: Five Things You Need To Know About the Current Airline Ticket Tax Controversy

Shashi Verma, TfL's director of customer experience, said: ''Pay as you go Oyster cards do not expire and customers are able to return their cards to a Tube ticket office at any time for a refund of the remaining balance and card deposit.

BBC: Unused Oyster cards valued at ?55m

Until recently, when you cancelled a ticket booked on Amtrak before the train left, the company would simply refund the money to your credit card.

ECONOMIST: Business travel