A coroner has slammed Samaritans' confidentiality policy and accused it of showing a “complete lack of co-operation” following a teenager’s death.

An inquest following the suicide of a mother whose son had died three months previously has ruled that the “uncooperative attitude” of Samaritans may have been a contributing factor to her death. Dennis and Suzanne Williams discovered that their 18-year-old son called the helpline charity before he drowned but, due to Samaritans' procedures on privacy, were unable to learn more about these conversations from the charity.

Samaritans has strict confidentiality rules which it says are essential to the service it provides.

The Daily Post in Wales reported that coroner Dewi Pritchard Jones criticised the charity for refusing to help with the enquiry into Matthew Williams’ death, saying that the charity only yielded after its chief executive was “threatened” with a summons to appear before the coroner.

Pritchard Jones told the inquiry in Llangefni: “The good thing to come out of the episode with the Samaritans is that they realise that, when coroners ask for assistance, it is to establish the circumstances of the death and not to ask why.

“My hope and indications from the Samaritans is there will be better co-operation in future.”

However, Samaritans has defended its confidentiality policy and stated that suicide is a complex issue which is likely to have several inter-related causes.

The charity’s chief executive, Catherine Johnstone, said: "Samaritans has the utmost respect for our callers’ privacy and we take this issue very seriously. This is an essential and greatly valued feature of the service we provide.

"We believe that without our promise to keep everything confidential, people who have the greatest need might never have the courage or trust to speak to us. This confidentiality has been in place since Samaritans was founded 60 years ago.”

She added: "In order to retain the integrity of our service this policy remains in place even if we never hear from our caller again.”

Matthew Williams went missing in April 2012, before being found in the sea at Malltreath in Anglesey on May 23. The cause of death was given as drowning.

His father called the actions of the charity “disgusting”.

Johnstone said there are only four circumstances in which Samaritans will release information obtained during a call, and in these circumstances it will fully co-operate in sharing the information held with the relevant authorities.

These are: if a caller directly asks them to; if a court order requires them to; they receive a call about an act of terrorism; or the safety of its volunteers or the delivery of its service is threatened.