MS sufferer Debbie Purdy is considering going to Dignitas
The UK has the third highest number of people registered with the Swiss suicide charity Dignitas, a BBC investigation has found.
The number of Britons on the group's list has risen to 725, behind only Switzerland and Germany, 5live found.
Dignitas says they have paid a fee, allowing them to book a date to travel to the country to end their lives.
There have so far been no prosecutions of relatives of 101 UK citizens who have used Dignitas' services.
Since Dignitas opened in 1998, UK membership has increased every year.
In Switzerland it is legal to aid and abet a suicide, provided it has not been carried out for a profit.
It is illegal in the UK and anyone convicted faces up to 14 years in prison.
Noel Martin, who is 49, is paralysed from the neck down and needs round-the-clock care, has registered with Dignitas.
He was left paralysed after a block of concrete was thrown through his car windscreen in Germany in 1996 and he hit a tree.
During a debate on BBC 5live, Mr Martin spoke with Liz Carr, who uses a wheelchair and also needs 24-hour care but has a different attitude towards living with a disability.
He said: "In order to exist, to live a life, you have to touch life or life touches you - and I haven't got any feelings, it's an empty vessel.
"You can't be alive, you're just existing."
But Ms Carr disagreed, saying: "I don't think I've met many people that are living more than you, that have more life than you have...
"I see how passionate you are... about love, about all the things that make us human."
Last month, a woman suffering from multiple sclerosis lost her High Court attempt to clarify UK law on assisted suicide.
Debbie Purdy, 45, from Bradford, has suggested that in the future she may want to travel to Dignitas to die.
She wants her husband by her side and sought clarification on whether he will be prosecuted on his return home.
But two senior judges said the current guidelines were adequate and did not require clarification.
While there have been no prosecutions to date, the Director of Public Prosecutions (DPP) has carried out investigations.
An investigation is currently under way into the death of Daniel James - the last Briton to die having enlisted Dignitas' help.
The 23-year-old, from Worcester, was paralysed in a rugby accident and ended his life last month even though he was not terminally ill.
His parents are being investigated by police and a report will be referred to the complex case unit of the Crown Prosecution Service.