Method of leak testing closed, filled containers (c, c u) characterised in that the method comprises the steps of: - loading containers (c, c u) into corresponding container holders (h, 101, 102, 103, 104, 105), wherein said container holders (h, 101, 102, 103, 104, 105) are adapted to be received by and removed from a first and second leak testing arrangement; - conveying the containers (c, c u) in their container holders (h, 101, 102, 103, 104, 105) to a first leak testing station comprising said first leak testing arrangement, wherein said first leak testing arrangement receives said container holders (h, 101, 102, 103, 104, 105); - subjecting the containers (c, c u) in their corresponding container holders (h, 101, 102, 103, 104, 105) to a first leak detection step (T 1), and rejecting together with their corresponding container holders (h, 101, 102, 103, 104, 105) containers (c f1) identified as leaking based on the first leak detection step (T 1); - removing the containers (c, c u) in their corresponding container holders (h, 101, 102, 103, 104, 105) from the first leak testing arrangement and conveying the containers (c T1) not identified as leaking in the first leak detection step (T 1) in their container holders (h, 101, 102, 103, 104, 105) to a second leak testing station comprising said second leak testing arrangement, wherein said second leak testing arrangement receives said container holders (h, 101, 102, 103, 104, 105) not identified as leaking in the first leak detection step (T 1); - subjecting the containers (c T1) not identified as leaking in the first leak detection step (T 1) in their container holders (h, 101, 102, 103, 104, 105) to a second leak detection step (T 2). - loading containers (c, c u) into corresponding container holders (h, 101, 102, 103, 104, 105), wherein said container holders (h, 101, 102, 103, 104, 105) are adapted to be received by and removed from a first and second leak testing arrangement; - conveying the containers (c, c u) in their container holders (h, 101, 102, 103, 104, 105) to a first leak testing station comprising said first leak testing arrangement, wherein said first leak testing arrangement receives said container holders (h, 101, 102, 103, 104, 105); - subjecting the containers (c, c u) in their corresponding container holders (h, 101, 102, 103, 104, 105) to a first leak detection step (T 1), and rejecting together with their corresponding container holders (h, 101, 102, 103, 104, 105) containers (c f1) identified as leaking based on the first leak detection step (T 1); - removing the containers (c, c u) in their corresponding container holders (h, 101, 102, 103, 104, 105) from the first leak testing arrangement and conveying the containers (c T1) not identified as leaking in the first leak detection step (T 1) in their container holders (h, 101, 102, 103, 104, 105) to a second leak testing station comprising said second leak testing arrangement, wherein said second leak testing arrangement receives said container holders (h, 101, 102, 103, 104, 105) not identified as leaking in the first leak detection step (T 1); - subjecting the containers (c T1) not identified as leaking in the first leak detection step (T 1) in their container holders (h, 101, 102, 103, 104, 105) to a second leak detection step (T 2).