London Stansted Airport has been named the worst for flight delays in the UK.
New figures from the Civil Aviation Authority show departures from the Essex airport were 25 minutes late on average last year.
London Stansted is the fourth busiest airport in the UK.
It is a hub for a number of low-cost eastern European airlines as well as being the largest base for Ryanair.
Birmingham and London Luton recorded the joint second worst punctuality performance, with aircraft typically taking off 19 minutes behind schedule.
Belfast City Airport was the best performer, with flights leaving just eight minutes late on average.
Liverpool was in second place at 10 minutes.
Rory Boland, editor of consumer magazine Which? Travel, said: ‘It’s completely unacceptable for passengers to be regularly delayed by nearly half an hour.
‘These delays aren’t just an inconvenience but can leave holidaymakers hundreds of pounds out of pocket because of missed connections, transfers and fines for picking up their hire car late.
‘While compensation is available for delays of over three hours, airlines should stop passing the buck and make it easier for their passengers by finally introducing automatic compensation.’
A spokesman for London Stansted said: ‘Following a particularly challenging summer last year when adverse weather and air traffic control issues had a dramatic impact on airline on-time performance, Ryanair committed to a multimillion-pound investment in additional resourcing and equipment to support its ground operation at London Stansted.
‘This investment has already helped deliver significant service improvements to flight punctuality.’