Media playback is unsupported on your device Media caption Paul Lamb: "I want to choose to call it a day"

A paralysed man is taking up the legal challenge previously mounted by the late Tony Nicklinson for the right to die with the help of a doctor.

Paul Lamb, 58, from Leeds, has joined forces with the family of Mr Nicklinson, who died in 2012.

Earlier this year, Nr Nicklinson's widow Jane won permission to continue the challenge to a High Court ruling against doctor-assisted death.

Anti-euthanasia campaigners say the current law protects vulnerable people.

The two cases will be heard in the Court of Appeal on 14 and 15 May.

In England and Wales, it is an offence to encourage or assist a suicide or a suicide attempt. The law is almost identical in Northern Ireland.

In Scotland there is no specific law on assisted suicide, although in theory someone could be prosecuted under homicide legislation.

BBC legal correspondent Clive Coleman says Mr Lamb's case goes beyond assisted suicide, because he is so badly paralysed that he could not take the final steps to kill himself.

He would need a doctor to kill him, which would amount to murder, our correspondent says.

'Pointless life'

In March, the Court of Appeal granted an order allowing Mr Lamb, who has waived his right to anonymity, to take over Mr Nicklinson's claims.

Analysis Paul Lamb's case goes far beyond assisted suicide. His paralysis is so severe that he could not take the final steps to kill himself. For example, if someone filled a syringe full of lethal drugs and gave it to him, he could not inject himself. So, like Tony Nicklinson, he would need a doctor to kill him. Under the current law that would amount to murder. For that reason he is seeking a declaration that any doctor who killed him would have a defence to a charge of murder. The defence is known as "necessity", meaning it was necessary for the doctor to act to stop intolerable suffering. The defence has been used in the case of conjoined twins where doctors ended one life in order to save another. A declaration that the defence would protect a doctor who ends a single life goes far beyond that and represents the most ambitious challenge yet to the law governing the right to die.

He is seeking a court declaration that any doctor who killed him would have a defence against such a charge.

The defence is known as "necessity", meaning it was necessary for the doctor to act to stop intolerable suffering.

Mr Lamb, who was severely injured in a car accident in 1990, has no function in any of his limbs apart from a little movement in his right hand. He says he has been in pain for 23 years, needs 24-hour care and his life consists of "being fed and watered".

In a statement to the courts, he said: "I am in pain every single hour of every single day. I have lived with these conditions for a lot of years and have given it my best shot.

"Now I feel worn out and I am genuinely fed up with my life. I feel I cannot and do not want to keep living. I feel trapped by the situation and have no way out.

"I am fed up of going through the motions of life rather than living it. I feel enough is enough."

Mr Lamb, a divorced father of two, said he was not depressed and just wanted to end his life in a dignified way, with his loved ones around him.

Threat to vulnerable people

His case is being supported by the British Humanist Association, which wants to establish the right to doctor-assisted death in certain circumstances.

Chief executive Andrew Copson said: "In the absence of legislation on assisted dying, we have to establish the right to a doctor-assisted death through the courts but we also hope that Paul's case will help to stimulate public debate on this issue, and convince Parliament to listen to the massive majority opinion in this country and legalise assisted dying."

However, Dominica Roberts, from the campaign group Care Not Killing, said "it would be very dangerous to give [doctors] the authority to kill".

She said there was a very small number of "very firm-minded people", such as Mr Nicklinson and Mr Lamb, who want the law changed, "but on the other side you have... perhaps hundreds of thousands of vulnerable people whom the law protects by the absolute blanket 'thou shalt not kill'."

Media playback is unsupported on your device Media caption Jane Nicklinson: "I will support anyone in the future that takes on this fight"

Disability rights group Scope also raised concerns about the risk to disabled people if legislation were changed.

Scope chief executive Richard Hawkes said: "We must avoid any temptation to change assisted suicide laws based on a couple of undeniably heart-wrenching and tragic cases."

In January, Mrs Nicklinson won permission to continue her husband's campaign and appeal against the High Court ruling that refused to grant him permission to seek medical assistance to die.

Mrs Nicklinson told BBC Breakfast: "In my mind the severely disabled are being blatantly discriminated against. Why shouldn't they have the same rights as everyone else? There would obviously be huge safeguards put in place so that people are protected."

Mr Nicklinson was paralysed from the neck down after a stroke in 2005 and suffered from locked-in syndrome. After refusing food and fluids, the father-of-two died from pneumonia at his home in Melksham, Wiltshire, on 22 August 2012.

He was one of several people to challenge the current laws on assisted dying. Diane Pretty, who was terminally ill with motor neurone disease and died in 2002, wanted the courts to give her husband immunity from prosecution.

Debbie Purdy, who has severe multiple sclerosis, challenged the lack of clarity on the law on assisted suicide. She won her case and guidance was issued in 2010, but the law did not change.