15/01/2015 12:35 GMT | Updated 17/03/2015 05:59 GMT

Our Right to Choose When We Die Is Widely Curtailed for Very Good Reasons

In 2009 I had the privilege of spending an afternoon, courtesy of the BBC, with Debbie Purdy. The roses of Regent's Park at their best, two wheelchairs converged - one with an multiple sclerosis (MS) sufferer, someone with motor neurone disease (MND) in the other, both with death sentences over them. We got on well. The BBC billed the encounter as an attempt to bring opposing views on assisted dying or suicide into some sort of synergy. It failed! Debbie wanted the possibility of going to Dignitas without the fear of her husband, Omar, being prosecuted. Then, she told me, she could live a full and free life. As a result of her court case, the DPP issued guidelines which would have protected Omar. Sadly though, last year she died in her local hospice having refused food for months. Ironically such palliative care is not so developed in countries where assisted suicide has been legalised.

Such exceptional cases make easy and expedient news stories, unlike the thousands more who die well in hospices or with palliative care at home. Debbie argued for the right to choose: finding 'dignity in taking control of the time and manner of... death'. Who could deny us that? The truth is our right to choose is widely curtailed for very good reasons. We're not free to drive as fast as we choose, or in what direction we choose, or to smoke wherever we choose. The reason is the public good, to protect the vulnerable. It's simply untrue that suicide affects no one else. Nor is it true that assisted dying is a purely personal matter.

A feature of a 'natural' death is that it allows the bereaved to grieve fully. They can vent their inevitable anger on someone, usually God, even if it's to say, "I can't believe in a God who allows this."

Or they may blame the inadequacies of doctors, the system or the government. But who can they be angry with if you've asked to die? They can't blame you; it was your wish. That leaves themselves, because their care wasn't enough, or the professional you enlisted. Angerless grief is a delusion.

Assisted dying is not a private matter, because it affects the doctors, nurses and pharmacists who are expected to perform semantic contortions and pretend that killing is a synonym for curing, and to desert their vocations as healers. That changes the doctor/patient relationship.

It's not a private matter because it endangers the dignity of those with disabilities or dementia. It opens the door to the proposition that some lives lack value, are less valuable than others. That in turn leads to such events as lethal injections administered to disabled infants and to the elderly who are 'tired of life'. No wonder the disabled community widely fears this Bill.

Assisted dying is not a private matter because, whatever the nominal safeguards, the elderly will experience pressure tantamount to bullying. Of course it won't usually be overt - just sighs, looks, asides, confirming the person's conviction that they are worthless, a 'burden' or a drain on resources of care, energy and future inheritance - and of the state. 'You're better off without me,' they sadly conclude.

It's not a private matter because it reinforces the primeval fear we humans have of the unknown. It sends the message that there's a shortcut to avoid the journey of dying. Its effect is twofold: it normalises that shortcut for a society, and it replaces in the public mind the last allies of life, hope and trust, with its only true enemy, fear, thus poisoning society's bloodstream.

The supposed 'safeguards' of Lord Falconer's Bill, the latest attempt to legalise assisted dying, are so porous that the Lords rightly allowed it to reach to committee stage. It was not an endorsement of the bill, more a 'let's examine what it really says.'

For example, the six-month prognosis is precarious (remember al-Megrahi's three months?); certification by any two doctors risks doctor-shopping. Amendments won't alter the experience in other jurisdictions, that once the line of legitimising the deliberate ending of life has been crossed, no amount of 'safeguards', even legal oversight, will hold back its extension.

It is rather like saying, "Turn round on the M25 if you choose. We'll design a car with air-bags, dodgem bumpers, bells and whistles. We'll have CCTV to check no one else gets hurt...." There are two possible outcomes: either a multiple pile-up and gridlock round London, or everyone else is sent in the same direction as you.

The Assisted Dying Bill is an attempt to slip under the radar of fear of dying. However, its effect would simply be to increase its range and power. The slippery, subjective concept of 'quality of life' will become a qualification for death.

Michael Wenham was diagnosed with Motor Neurone Disease in 2002, which was later confirmed as the PLS variant. He is totally dependent on his wife for care.