Developed by Philip Nitschke, one of the founders of Exit International, whose Irish branch is led by Tom Curran, the ‘Sarco’ (short for sarcophagus), is a coffin-shaped machine that releases deadly nitrogen once activated from inside.

Nitrogen gas is also used as a method of execution in US states, such as Alabama.

The capsule has raised a host of legal and ethical questions in Switzerland, where active euthanasia is banned but assisted suicide has been legal for decades. With assisted suicide you are given a lethal substance but administer it to yourself.

In a statement, the public prosecutor’s office of the canton of Schaffhausen said it has “opened criminal proceedings against several people for inducement and aiding and abetting suicide… and several people have been placed in police custody”.