According to new research Manchester Airport has the longest average security queues of the UK's largest airports.
Average waiting times at the northern hub range from 17 minutes at Terminal 1 to 15.5 minutes at Terminals 2 and 3, a Which? survey suggests.
The fourth worst performance was at Stansted (13.7 minutes), followed by Luton (11.7 minutes).
Heathrow Terminal 5 record the shortest average time, according to the study, at 8.6 minutes.
Some 4,499 passengers were asked to provide an estimation of how long they waited at security on their most recent visit to UK airports.
One holidaymaker told Which? they queued for up to 90 minutes at Manchester.
The consumer group said the airport appears to have downgraded its waiting time targets from getting 95% of passengers through security in less than eight minutes in 2017, to getting 92% through within 15 minutes today.
The study ranked Belfast International as the worst small airport for security queues, with a typical wait time of 22 minutes.
Rory Boland, editor of Which? Travel magazine, said: "Never-ending queues through security are a pain at the best of times, but if you are left waiting for hours on end you could find your flight has left without you.
"To add insult to injury, if this happens you are unlikely to qualify for compensation as the time it takes to get through security is out of the airline's control.
"Airlines will rarely delay a flight due to long queues at security so it's important to arrive at the airport in plenty of time, especially if you are flying from Manchester or Belfast."
A spokesman for trade body the Airport Operators Association said: "Which?'s self-selecting survey does not reflect the experience of the millions of passengers travelling through UK airports every year.
"As data from both our regulator, the Civil Aviation Authority, and the Department for Transport show, the majority of the public believes that airports get the balance right at security, delivering to the highest standards both for their safety and their travel experience.
"Nevertheless, airports continuously invest to improve our passengers' experience of airport security and as a result, 85% of passengers were satisfied or very satisfied with their security experience in 2018 according to the Department for Transport."