Drone near-misses with planes have more than tripled in two years, new figures show.

Some 92 incidents were recorded in 2017, according to analysis of UK Airprox Board (UKAB) data.

This is compared with 71 during the previous 12 months and 29 in 2015.

Former RAF and British Airways pilot Steve Landells, flight safety specialist at pilots' union Balpa, described the figures as "very worrying".

He believes the true extent of the problem could be even more severe as pilots struggle to see drones from cockpits.

"It's really hard to see something that small," he said.

"There's a possibility there are a lot more near misses that aren't being seen," he said.

"This could just be the tip of the iceberg."

Twenty-eight near misses in the past year were classified as having the most serious risk of a collision.

These included incidents near the London airports of Heathrow, Gatwick and London City, as well as Edinburgh, Manchester, Liverpool and Bristol.

Mr Landells explained that pilots are particularly concerned about near misses which occur when they are preparing to land.

"It's a critical stage of the flight and you really don't need to be distracted," he said.

"If you see a drone flying past your cockpit it's a real shock to the system.