A planned drone protest at Heathrow Airport tomorrow "will not be tolerated", police have said.
Climate change activists have announced plans to fly toy drones at the busy airport on Friday 13 in an effort to ground flights and put pressure on the government to reduce the UK's carbon emissions.
They are also calling for a stop to the planned expansion of the airport.
The Metropolitan Police have urged those planning on taking part to reconsider, or expect arrest and prosecution.
They also pledged to deploy extra officers to tackle "unique challenges that come with a protest targeting the airport".
Deputy assistant commissioner, Laurence Taylor said: "Far from this being a lawful protest, this is a deliberate and criminal targeting of an essential part of the UK's national infrastructure that thousands of people rely on every day and it will not be tolerated.
Heathrow Airport have issued a statement about the protest action
"We would urge anyone planning to take part in this activity to reconsider. Airspace around all airports is restricted for public safety and security, and we take the flying of a drone within airspace used by passenger planes very seriously."
The action is being carried out by Heathrow Pause, a splinter group of the Extinction Rebellion movement.
Heathrow Pause organiser Larch Maxey told talkRADIO’s Eamonn Holmes there was no safety issue.
“It’s all completely open and transparent we told the authorities six weeks ago what we were going to do,” he said.
“It’s a completely safe action it doesn’t endanger anyone’s life. It’s toy drones flown at head height away from the airport, not in a flight path.”
Heathrow Airport have announced that they will use "drone mitigation and detection systems" to ensure the disruption to passengers is minimised.
"We agree with the need to act on climate change, but it is through constructive engagement and action that real progress will be made," they said in a statement.
"Attempting to disrupt hard-working passengers and families taking flights, will not solve the issue."
Extinction Rebellion had planned to carry out their own drone protest earlier this year, but later called off the action.