Holidaymakers are being warned they face lengthy delays at European airports this summer after border checks were tightened.

Passengers have been forced to wait in queues for up to four hours - longer than some of their flights - after arriving at airports popular with British tourists.

The delays are reportedly being caused by the introduction of newly-toughened and more time consuming immigration checks.

The problem - at what is traditionally already the busiest time of the year for flights - is being made worse by a lack of border officials on the continent, it is claimed.

An association representing airlines said queues stretching for "hundreds of metres" are in some cases causing passengers to miss their flights.

It warned that "shameful" queues can be expected at airports including Madrid, Palma, Lisbon, Lyons, Paris Orly, Milan and Brussels. Some flight delays have increased by 300 per cent in a year, it claimed.