Climate change activists have threatened to attempt to shut down Heathrow airport for 10 days next month.
Extinction Rebellion says it will stage a one-day demonstration at the airport in June ahead of 10 days prolonged action in July unless the government performs a U-turn on plans to allow Heathrow to expand via the building of a third runway.
The group made headlines for several weeks in April after protests and vigils shut down areas of central London, including Parliament Square and Waterloo Bridge. More than 1,000 people were arrested.
A leaked consultation document shared between members of the group suggested Extinction Rebellion may use drones to shut down Heathrow, the BBC reports.
However, the group has since distanced itself from this course of action, stating it would not take action that would put airline passengers at risk and described interpretations of the leaked plans as having been “misconstrued”.
A Heathrow airport spokesperson said: "This is reckless action that, if carried out, could endanger the lives of the travelling public and our colleagues.
"We agree with the need to act on climate change, but that requires us to work together constructively – not commit serious criminal offences just as hard-working people prepare to spend a well-earned holiday with their family and friends."
Aviation minister Baroness Vere said the perpetrators of any attempts to halt operations at Heathrow through illegal means would “be met with the full force of the law”, stressing using drones in a manner that could put people’s safety at risk carried a maximum life sentence.
In April, Extinction Rebellion demonstrators took their protest to Heathrow but did not cause any disruption to flights.
The Home Office announced new police powers in January to combat illegal drone activity while extending existing exclusion zones around airports.
Police will be given additional powers to land, seize and search drones, while the government will expand the use of technology to detect and repel drones from sensitive sites like airports.
The move followed 36 hours of disruption at Gatwick airport shortly before Christmas last year, owing to what was believed to be drone activity in and around the airfield.
Heathrow was also forced to suspend operations briefly in January following a reported drone sighting.