Waiting at the airport in Antigua on Friday evening with her 10-year-old son, Shemar, Shemika Simon must have wondered whether she would ever make it to Britain in time to spend Christmas with her family. Earlier in the week, Gatwick airport, her intended destination, had been plunged into chaos by the sighting of a drone hovering near its runway. Its reappearance on Friday did not bode well.

“My heart was in my hand when I saw the drone – I thought our flight would be cancelled,” said Simon. But, by midday yesterday, she had arrived at Gatwick. The experience, though, had left her bewildered. “It’s crazy that a drone could cause so much disruption and actually take flights off course.”

Crazy but predictable. For years, aviation experts, pilot groups, MPs and peers have been warning that a drone could unleash mayhem at a busy British airport. It was a question of when, not if, they said.

The government, though, appears not to have been overly worried.

Two years ago, in response to concerns raised in parliament by Paul Flynn, the then transport secretary, Patrick McLoughlin, insisted “there is no complacency whatever from the government on the use of drones”.

The same year, Lord Harris presented a report to the London assembly that called for the government to examine whether “the current legislation relating to the use of drones is suitable” and for ministers to “explore technological options to improve the capacity to restrict drone use or disable them”.

Shemika Simon with her son Shemar after landing at Gatwick. Photograph: Amy Walker/The Observer

But a long-awaited drones regulation bill, which had its first reading in parliament in 2017, has been kicked into the long grass. The government’s focus on Brexit, and its reluctance to impose new laws that could antagonise firms seeking to profit from drones, have been blamed for the delay which comes as reported near-misses involving the aircraft continue to rise.

The UK Airprox board, which tracks air safety, records that in 2018 there were 117 confirmed incidents involving drones and aircraft confirmed compared with 93 in 2017. In the US and elsewhere drone sightings by pilots are also increasing.

Earlier this month, a 737 jetliner approaching Tijuana, Mexico, was badly damaged after a suspected collision with a drone. “It’s not uncommon to have airline pilots report sightings of drones,” said Richard Parker, chief executive and founder of Altitude Angel, a company that makes airspace management technology, who is critical of the idea that more regulation could have prevented the chaos at Gatwick.

“Airport incursions are not going to go away – but the impact we’re seeing at Gatwick isn’t because the drone was in its airspace, it’s because the airport can’t direct a security response as it doesn’t know where the drone is going to be and when.”

Trials using specialist drone detection technology provided by Altitude Angel will start in the new year at six airports around the UK following a successful demonstration at Manchester airport in November where a “rogue drone” scenario – in this case the drone entering the path of landing aeroplanes – was played out. Parker estimated that the necessary drone detection radar, radio frequency sensors and specialist software to protect an airport would not represent a huge outlay.

“It’s probably not even £1m – that’s not a lot compared with what it’s costing the airlines today. A lot of people will be wondering why they haven’t spent this money sooner.”

This view was echoed by a commentator on the Professional Pilots Rumour Network forum who complained: “This problem was always going to appear and the people who have shown themselves utterly unprepared are the board of Gatwick Airport Ltd.”

A spokesman for the airport insisted that it had embraced anti-drone technology.

“While Gatwick has been trialling a selection of systems that might help detect and disrupt drones for some time, there is no single proven commercial solution available that could have prevented the sustained, prolonged and unprecedented attack that occurred at the airport recently.”

Drone use is becoming more common and pilots have reported an increasing number of drone-related incidents. Photograph: Joe Giddens/PA

Dr Simon Moores, a security futurist and risk consultant, said the aviation industry would always be one step behind the drone threat: white label parts (components made by one manufacturer who sells to others who market it as their own brand) bought off the internet can be used to build unregistered drones; lithium batteries can now last up to three hours allowing for considerable disruption; technologies such as geo-fencing which create invisible boundaries around defined areas, can be bypassed.

“There exist no truly practical and cost effective solutions for large airports in a fast-moving arms race with a new generation of drones,” Moores said.

Special electromagnetic weapons – such as the drone guns carried by Donald Trump’s security detail and made by the likes of Kalashnikov – are capable of jamming a drone’s radio frequencies. But it is illegal to interfere with radio spectrum in the UK, which may explain why the army – which is exempt from these laws – was drafted in at Gatwick on Friday.

The belated military response was a troubling reminder that drones can present a more sinister threat. In 2015 drones were flown close to several French nuclear facilities, prompting fears that they could be used to target critical infrastructure. More recently, Islamic State has used them for reconnaissance while gangs use drones to ferry drugs over prison walls. Experts question how long before the devices drop more deadly payloads.

On Saturday, as Gatwick returned to normal, passengers gave a collective sigh of relief and expressed the hope that the chaos of last week acts as a wake-up call.

Clive Marsden, 65, who had flown in from Aberdeen, seemed to speak for many of his fellow passengers.

“It was surprising that they hadn’t thought this could happen. I don’t know why they didn’t shoot it down.”