Test case by Tony Nicklinson seeks declaration that any doctor terminating his life will be protected against murder charge

A man paralysed from the neck down after suffering a stroke that left him with locked-in syndrome will on Monday begin a high court battle to allow doctors to end his life.

In the most ambitious attempt yet to loosen laws on the right to die, Tony Nicklinson, 57, wants a declaration that any doctor terminating his life will have a "common law defence of necessity" against any possible murder charge.

The test case raises "difficult legal, moral and ethical questions", said Nicklinson's solicitor Saimo Chahal.

The Guardian understands lawyers for the Ministry of Justice will argue the case should be "struck out" as such a change in law would be for parliament and not the courts.

Nicklinson, a former rugby player who worked as an engineering executive in the Middle East, suffered a stroke in Athens in 2005 that left him paralysed, though he is not in a vegetative state.

He can move his head and eyes, and can communicate through use of an Eye-Blink computer or Perspex alphabet board. The married father of two from Wiltshire cannot speak, is fed liquidised food, and dependant on carers.

His disability means he cannot take his own life other than by slow starvation. He wants the right to die at home surrounded by his family rather than travelling to Switzerland, where medically assisted euthanasia is legal. And in any event, he is physically unable to administer any lethal drugs himself, a requirement by the Swiss Dignitas organisation.

His high court application goes far beyond assisted suicide. The director of public prosecutions guidelines on assisted suicide, which list mitigating factors against individuals being prosecuted for assisting suicide, do not apply as Nicklinson cannot be helped to kill himself; he must be killed.

"We are saying there should be a defence to the law of murder and want a declaration that it would be lawful for a doctor to administer a lethal drug to terminate Mr Nicklinson's life," said Chahal.

Lawyers say the case bearing most similarity in legal and ethical terms is that of the Maltese conjoined twins Rosie and Grace Attard, known as Mary and Jodie. Born in October 2000 and joined at the spine, the twins were separated in Britain after a far-reaching court order against the wishes of their parents because Rosie could not survive independently and the lives of both were at risk. Rosie died on separation.

Nicklinson, who has two daughters, Lauren, 24 and Beth, 23, with his wife Jane, and who lives in Melksham, suffered the stroke while working for a Greek civil engineering firm based in the United Arab Emirate.

He has said in previous statements: "What I have to look forward to is a wretched ending with uncertainty, pain and suffering whilst my family watch on helplessly.

"Why must I suffer these indignities? If I were able-bodied I could put an end to my life when I want to. Why is life so cruel?".

His lawyers say he is mentally competent, can make decisions about life and believes fervently in the right to self determination.