The Brazilian son of Great Train Robber Ronnie Biggs is fighting to stay at his bedside.
Solicitors representing Mr Michael Biggs are challenging a decision by British Home Office officials to order him to quit the country by September 24th or face deportation after they refused to renew his visa.
He suggests the blow could finish off his father, who is in the medical wing of London's Belmarsh prison suffering from brain damage and unable to speak or eat after suffering a fourth stroke.
"I am deeply distressed about this. All I want is to be with my father," he says. "I'm all my father has and I'm the only one who can understand him. We are very close. It would destroy him and me if we were parted.
"I don't understand why the authorities have done this. I'm no threat to anyone and my father certainly isn't. It's inhumane. I'm very upset."
Michael Biggs, who is campaigning for his father's release, came to Britain when Ronnie returned and gave himself up in May after 35 years on the run.
Last week, Michael's 26-year-old girlfriend Ms Veronica Carvalho and one-year-old daughter Ingrid joined him in the UK. But he isn't entitled to British citizenship because his father never married his Brazilian mother, former stripper Raimunda Rothen.
Michael is now suing for the right to stay under the Human Rights Act, which was recently made part of British law. His solicitor Ms Alison Stanley, head of the immigration department at London firm Bindman and Partners, says: "The decision to refuse Michael seems harsh as his father is so ill.
"There is no question of Michael staying here permanently or of him claiming any state support whilst he is here. All he wants is to be in the UK with his father while his father's health is so precarious and to support him in his application to the Criminal Cases Review Committee."
Biggs, now 71, was given 30 years for robbing the Glasgow-London mail train of £2,600,000 in the Great Train Robbery of 1963. He served only 15 months before fleeing Wandsworth Prison in 1965 and embarking on a playboy lifestyle in Brazil.