The police have resisted suggestions they have effectively legalised assisting a suicide – a crime that still carries a heavy punishment.
Record numbers of Britons travelled to a Swiss assisted suicide facility last year but no one has been charged.
And now new guidance from the Association of Chief Police Officers (ACPO) allegedly highlights the complications of investigating assisted suicides abroad.
Last year 33 Britons went to Swiss suicide clinic Dignitas to be helped to die – the highest ever annual figure.
Of the cases passed to prosecuters by the police, no one was charged.
The Care Not Killing Alliance warned: “It is extremely worrying that police officers are saying they cannot investigate and are advising their members not to investigate deaths abroad.”
Mark Pritchard, a Conservative MP who is vice-chairman of the Parliamentary Pro-Life Group, said: “I fear assisted suicide is being legalised by the back door.
“If the will of Parliament is being ignored, there should be an urgent review by the Justice Secretary.”
Kevin Fitzpatrick, of the campaign group Not Dead Yet, commented: “The idea is gaining hold that assisting someone to commit suicide is not prosecutable in practice.”
Aiding or encouraging a suicide remains illegal in England and Wales under the 1961 Suicide Act and punishable by up to 14 years’ imprisonment.
The Association of Chief Police Officers’ guidance on investigating assisted suicide has not been revealed in full, but the Mail on Sunday newspaper was shown the section which deals with deaths abroad.
The guidance says, “there may be a lack of co-operation or even a legal impediment as to why the relevant foreign authorities cannot provide evidence as to how and why someone has died”.
In a statement ACPO said: “The police service is responsible for investigating cases of encouraging or assisting suicide, whether the actual suicide takes place in the UK or abroad and whenever we receive information or intelligence about such a case, these investigations are pursued.”
The Crown Prosecution Service said: “Any inference that the CPS has implemented a blanket policy of not prosecuting for this offence is wrong.”