Despite the publicity given to Swiss suicide clinics, not all Swiss are happy with a law which allows foreigners to seek help in killing themselves. Prosecutors in Zurich are now calling for an investigation into claims that some patients are merely depressed and not terminally ill or suffering incurable pain. Some foreigners die within hours of arriving in Switzerland, which suggests that they have not been given a thorough medical and psychological examination.

Andreas Brunner, the senior prosecutor of the Zurich canton, told the London Sunday Telegraph: “We are not trying to ban the so-called death tourism, but the outsourcing of suicide must be put under stricter control… There are many cases where it is not clear whether the assisted person has chosen death in full possession of their decision-making capacity. But investigations are difficult due to lack of evidence after the suicide.”

The founder of the suicide group Dignitas, Ludwig Minelli, dismissed Mr Brunner’s complaint and accused him of crusading against his organisation. “If the investigations had a real basis I would have been summoned for questioning, but this has not yet happened,” he said.