People who have paid extra to reserve a specific seat on a plane and then been made to sit somewhere different. This is usually because they've tried to reserve the seats with extra leg-room.

In some instances, airlines are refusing to refund the cost because their terms and conditions state they can never guarantee you'll get the seat you choose.

One company claims this is because you may be travelling in a different plane to the one shown in the seating map you use to choose your seat from when booking online.

However, Under consumer law, companies cannot get away with charging you for something they then don't deliver.

Make a formal complaint to the airline and demand a full refund of your seat reservation fee.

Say the fee you paid for that particular seat was a separate charge on top of the ticket price.

Add that you were not just requesting a seat in the same way anyone travelling on a plane can do when they check in.

This principal also applies to train journeys. If you've booked a particular seat and cannot sit there, complain to the company. Say that under section 41 of National Rail's Rights of Carriage you are owed a partial refund as your seat reservation wasn't honoured.

There's no rule setting out how much you will get back as private rail firms can decide this for themselves.

You'll need proof of your ticket reservation. If you can, take a picture of the seat number you ended up sitting in on your phone.

When downgraded, e.g. when a passenger receives a seat on the plane corresponding to a lower class of service than that of the reservation, the airline should reimburse between 30 and 75 percent of the ticket price, depending on flight length.

Article 10 Regulation (EC) No 261/2004

1. If an operating air carrier places a passenger in a class higher than that for which the ticket was purchased, it may not request any supplementary payment.

2. If an operating air carrier places a passenger in a class lower than that for which the ticket was purchased, it shall within seven days, by the means provided for in Article 7(3), reimburse

(a) 30 % of the price of the ticket for all flights of 1500 kilometres or less, or

(b) 50 % of the price of the ticket for all intra-Community flights of more than 1500 kilometres, except flights between the European territory of the Member States and the French overseas departments, and for all other flights between 1500 and 3500 kilometres, or

(c) 75 % of the price of the ticket for all flights not falling under (a) or (b), including flights between the European territory of the Member States and the French overseas departments.