BBC News Online looks at the difference between UK and Swiss attitudes to assisted suicide.

Why did Reg Crew want to die?

Reg had motor neurone disease, a progressively disabling illness that is fatal is every case.

Although there is a drug that can hold back the progress of the disease, there is no cure.

The symptoms are gradual paralysis - the patient lose the ability to move, even though his or her mental faculties remain completely intact.

Eventually, the disease affects the ability to breathe.

Mr Crew said he had "had enough" and wanted to end his life.

However, he no longer had the ability to commit suicide independently.

So why couldn't he be helped to die in the UK?

UK law is quite clear on this - anyone who had helped Mr Crew to die would be committing a serious offence, punishable by imprisonment.

The most recent court challenge to this was thrown out at the High Court and by the Law Lords.

Diane Pretty, who was also in the advanced stages of motor neurone disease, challenged those decisions in the European Court of Human Rights.

However, the court rejected her claim that the UK courts and DPP had contravened her human rights by refusing to give protection to her husband.

Mrs Pretty died of natural causes shortly after the final ruling.

The UK government says it is not planning to review the law on assisted suicide.

What's different in Switzerland?

In theory, very little - there is no law actually permitting assisted suicide.

However, the Swiss authorities have a slightly more relaxed view.

It appears their view is that euthanasia of terminally-ill patients is a "humane act".

Prosecution is unlikely unless it is seen that the person helping someone to die is doing so for selfish reasons, such as an inheritance.

Here the Swiss law is clear - anyone assisting a suicide with these motives could get up to five years in prison.

The campaigners see the absence of a complete ban on assisted suicides as tacit permission to proceed - although their stance has never been tested in the Swiss courts.

Who or what is Dignitas?

Dignitas is one of a few Swiss organisations whose aim is to facilitate assisted suicide.

It has helped organise euthanasia for more than 100 people from both Switzerland and elsewhere.

It is run by a lawyer, Ludwig Minelli, who believes that he is helping people "die with dignity".

People wishing to take advantage must apply to Dignitas.

Once they arrive in Switzerland, a doctor examines them to verify their medical state, and makes a judgement on whether they are capable of making a balanced decision about suicide.

If they pass these tests, then provides the drugs - usually barbiturates - necessary to kill them.

These are not actually delivered by the doctor - the aim is that the patient performs the final act of either swallowing tablets or opening the valve on a drip.

The deaths are witnessed by two people and the local authorities informed.