Consumers may be missing out on billions in compensation for delayed flights, as airlines defer payouts to passengers who have been held up.

Flight delay data shows, 3.27 million passengers travelling to and from UK airports each year may have a potential claim.

The European Commission introduced the compensation laws 10 years ago.

With an average claim of around €430, that means €1.4bn a year in compensation may be available for passengers who have been delayed more than three hours.

But lawyers say it is just recently that landmark court rulings have helped establish a clear precedent.

Coby Benson, an aviation lawyer with Bott & Co, who helped establish this area of law in the UK, said: "The intention of the European Commission is that lawyers should never have been involved in this the first place."

"It was supposed to be a very easy system for passengers to gain compensation themselves when their flights are cancelled or delayed or they have been denied boarding."

"It's just unfortunate that the airlines more often than not make it extremely difficult for passengers to claim compensation and put obstacles in their way."

Europe-wide legislation was introduced in 2004, which says that if your flight is delayed by more than three hours and not caused by "extraordinary circumstances" like freak weather, volcanic ash, or terrorism, passengers are entitled to claim some compensation.

The amount consumers can claim ranges from €250 to €600, depending on the distance travelled and length of delay.

Richard Rubin, of the claims management website Refundme.com, says some airlines are quicker to pay compensation than others.

He says his firm deals with around 300 different carriers.

"There is a small minority who just flaunt the law, disrespect the law and fob off the consumer."