Drone Altitude Limit in the UK: The 120m Rule Explained

The 120 Metre Rule

Under UK drone regulations for the Open category, no unmanned aircraft may be flown at a height greater than 120 metres (approximately 400 feet) above the surface. This limit is measured from the ground or water directly below the drone, not from the take-off point. If you are flying on a hillside, the relevant measurement is always from the terrain beneath the aircraft.

This rule applies to all drones and model aircraft operating in the Open category, regardless of their weight class (A1, A2, or A3). It is one of the fundamental restrictions set by the Civil Aviation Authority (CAA) and is consistent with the altitude limits used across most of Europe.

Why 120 Metres?

The 120-metre ceiling exists to create a vertical buffer between unmanned and manned aircraft. Most manned aircraft — including helicopters, light aircraft, and commercial airliners — operate above 500 feet (approximately 150 metres) in uncontrolled airspace. The 120-metre limit provides a safety margin of at least 30 metres between the highest permitted drone altitude and the lowest typical manned flight altitude.

Without this separation, the risk of a mid-air collision between a drone and a manned aircraft would increase substantially. Even a small drone can cause catastrophic damage to a helicopter rotor or aircraft engine.

How Altitude Is Measured

Altitude in the context of drone regulations means height above the surface, not above sea level. This distinction matters in several scenarios:

• Flat terrain: The measurement is straightforward. If your drone is 120 metres above the ground at your location, you are at the legal limit.
• Hilly or sloping terrain: You must maintain no more than 120 metres above the ground directly below the drone at all times. If you fly from a hilltop over a valley, the ground level drops and your effective height above the surface increases.
• Near buildings or structures: You may fly up to 120 metres above the surface, but you must also consider the height of structures and maintain safe distances from them.

Most consumer drones display altitude as height above take-off point. This reading can be misleading over uneven terrain. You are responsible for ensuring compliance with the 120-metre limit above the surface.

Flying Higher: Operational Authorisation

If your operation requires flying above 120 metres, you can apply to the CAA for an Operational Authorisation (OA). This moves your operation into the Specific category, which requires a more detailed risk assessment and, in most cases, completion of the SORA (Specific Operations Risk Assessment) process.

An OA application must demonstrate that the risks of flying above 120 metres have been identified and mitigated to an acceptable level. This typically involves:

• A detailed Concept of Operations (ConOps)
• A SORA risk assessment
• Evidence of appropriate qualifications (usually a GVC as a minimum)
• An operations manual
• Adequate insurance coverage

Processing an OA application can take several weeks. Plan well in advance if you need to fly above the standard limit.

Penalties for Exceeding the Limit

Flying above 120 metres without authorisation is an offence under the Air Navigation Order 2016. Enforcement is carried out by the CAA and, in some cases, the police. Penalties can include prosecution and an unlimited fine. Repeated or reckless breaches may also result in the revocation of your Flyer ID and Operator ID.