(Reuters) – London’s Gatwick and Heathrow airports have ordered military-grade anti-drone defenses worth “several million pounds” after drones caused three days of disruption at Gatwick last month, The Times newspaper reported on Thursday.

Transport Minister Chris Grayling met police, aviation and defense chiefs on Thursday to discuss the issue, the report said. The airports did not immediately comment on the report.

Drone sightings caused chaos at Gatwick, Britain’s second busiest airport, last month, disrupting the travel plans of tens of thousands of people in the run up to Christmas.

The incident revealed a vulnerability that is being scrutinized by security forces and airport operators worldwide.

The military was drafted in to deploy specialist equipment, enabling authorities to reassure the airport that it was safe for planes to take off and land.

The technology included the Israeli-designed Drone Dome system, The Times reported.

Security minister Ben Wallace said last month Britain’s security forces had detection systems that could be deployed throughout the country to combat the threat of drones.

Media reports suggested that the defense ministry had since removed its anti-drone hardware from Gatwick.