US retail giant Amazon has received SAIL 4 operating authorisation and flightworthiness validation from the UK Civil Aviation Authority (CAA) for its Prime Air drone delivery service.

The authorisation allows Prime Air to operate over more densely populated parts of Darlington, in north-east England, and to expand operations in and around the town.

Amazon said it is the “first” drone operator globally to obtain both approvals at SAIL 4, which stands for Specific Assurance and Integrity Level.

The level sits within the UK Specific Operational Risk Assessment framework for advanced drone operations.

SAIL 4 is classified as medium- to high-risk, requiring operators to demonstrate technical controls, system integrity and safety-management processes for complex drone operations.

Amazon expects eligible households in the area to rise from approximately 600 to around 8,000.

The retailer uses its MK30 delivery drone for the service.

The aircraft includes detect-and-avoid technology designed to identify other aircraft, people, animals and physical obstacles, as well as a secondary flight-control system intended to take over if the main system detects an irregularity.

The service is available to Prime members with a garden or driveway within a 7.5 mile (12km) radius of Amazon's Darlington fulfilment centre.

Eligible products must weigh no more than 5lb (2.2kg) and fit within the aircraft's carrying capacity.

Prime Air launched in Darlington in early 2026 under CAA authorisation for beyond-visual-line-of-sight operations in less densely populated areas.

Amazon announced plans to introduce Prime Air in the UK in 2023 and confirmed Darlington as its first location in 2025.

It marks the company's first expansion of the service outside the US.

Prime Air Europe director Theunis Scheepers said: “Prime Air is the first in the world to receive a SAIL 4 approval from the UK Civil Aviation Authority.

"For customers in Darlington it means getting what they need quickly, safely, and reliably, and it is the foundation for bringing Prime Air to more of the UK.”

Elsewhere in Europe, Amazon conducted initial test flights in San Salvo, Italy in late 2024 but the group halted the project and withdrew its regulatory applications in December 2025 following a strategic review.