10/09/2015 07:43 BST | Updated 10/09/2016 06:12 BST

It Is Impossible to Justify the Continuation of Our Unjust Laws on Assisted Dying

My first incursion into the debate was in 2009 when Debbie Purdy, who suffered from progressive multiple-sclerosis, persuaded the highest court in the land to require me, as the then director of Public Prosecutions, to publish guidelines setting out the approach taken to prosecuting assisted suicide cases. I decided to act swiftly.

Two principles underpinned my approach. First, that the criminal law should rarely (if ever) be used against those who compassionately assist a loved one to die at their request - so long as that person had reached a voluntary, clear, settled and informed decision to end their life. Second that very strong safeguards are needed to protect those who might be pressurised (in any number of ways) into taking their own lives: those who encourage the death of the vulnerable should feel the full force of the law.

Since then hardly anyone has questioned those principles. I personally oversaw over 80 decisions not to prosecute in cases of assisted suicide without provoking outrage or a clamour for a change of approach. And a motion welcoming my guidelines was unanimously supported by MPs on all sides of the House in a Backbench Business Committee debate in the House of Commons in March 2012.

However, over the years I have become increasingly concerned about two inherent limitations in the guidelines. The first is that although those who have reached a voluntary, clear, settled and informed decision to end their lives can now be confident of the compassionate assistance of loved ones without automatically exposing them to the criminal law, the only assistance they can be provided with is the amateur help of those nearest and dearest. They cannot be provided with professional medical assistance unless they traipse off to Dignitas in Switzerland.

The second inherent limitation in the guidelines goes to the heart of the argument advanced by those who do not want any change in the law. They, rightly, point to the risk that some people might be pressurised or encouraged to take their own lives by those who do not have their best interests at heart; and argue the blanket criminalisation of assisted suicide, subject to the operation of my guidelines, offers the best protection against abuse.

I have always given great weight to that argument. I completely accept the case for very strong safeguards to protect those who might be put upon (in any number of ways) to take their own lives. But the truth is that the only safeguard that I was able to put in place in my guidelines was an 'after the event' criminal investigation into the motive of the individual who assisted their suicide. As the President of the Supreme Court observed in the Nicklinson case:

"A system whereby a judge or other independent assessor is satisfied in advance that someone has a voluntary, clear, settled and informed wish to die and for his suicide then to be organised in an open and professional way, would... provide greater and more satisfactory protection for the weak and vulnerable, than a system which involves a lawyer from the DPP's office inquiring, after the event, whether the person who had killed himself had such a wish".

The safeguards in the Assisted Dying Bill proposed by Rob Marris MP are certainly strong and robust. A person may only be provided with assistance to end his or her life if a High Court judge sitting in the Family Division, by order confirms that he or she is satisfied that the person has a voluntary, clear, settled and informed wish to end his or her own life. An order can only be made if the person in question has made a declaration about their wish to end their life, which must be counter-signed by a witness who must not be a relative or a person directly involved in the person's care or treatment. And only those diagnosed by a registered medical practitioner as having a terminal illness and less than six months' life expectancy may apply to the High Court.

So, in the end, the question before Parliament this Friday is whether we have got the balance right under the current law. At the moment, those with a voluntary, clear, settled and informed decision to end their lives can receive assistance to commit suicide, but only the amateur assistance of loved ones unless they have the means and physical ability to travel to Dignitas in Switzerland. Professional medical assistance so that they can die with dignity and in peace at home is denied.

Parliament now has the opportunity to re-balance our law in this difficult and sensitive area. Unless we revert to a position of a blanket prohibition of any assistance even for those with a voluntary, clear, settled and informed decision to end their lives, we have to recognise and accept their desire for professional help from medical practitioners rather than amateur help from loved ones. So long as the robust and strong safeguards in the Assisted Dying Bill are enshrined in law, that desire can be met without compromising the protection necessary to protect the vulnerable. In such circumstances, it is impossible to justify the continuation of the injustice inherent in the current arrangements.

Keir Starmer is the Labour MP for Holborn and St Pancras, and a former director of Public Prosecutions