Samir el Sawy, 49, a diabetic with chronic renal failure, has been on dialysis at the Hammersmith hospital in west London for the past six years. After a transplant failed because his body rejected the kidney, Mr Sawy travelled to Egypt to establish whether any of his family there were potential donors. His four brothers were unsuitable, but his son, Ehab, 20, was found to be potentially suitable.
Immigration officials at the British embassy in Cairo rejected Ehab el Sawy's application, however, on the grounds that he was "a young, single man with imminent compulsory military service to complete" and that there was no evidence of his father's financial ability to "cover the necessary expenses of your visit".
"I have had several operations and my body is covered in scars so that I have few veins left suitable for dialysis," Mr Sawy said at his home yesterday. "My son, who is by my first wife, offered himself to come to London and save my life, but they won't allow him into the country."
He said his first wife, Mahasen, was killed in a car accident several years ago and Ehab has been raised in Egypt by his grandmother because he never wanted to live in Britain.
His friend, Adel Takla, who has been raising funds for Ehab's visit to London through the Egyptian Coptic Orthodox Church, said: "It is insulting that the boy travelled to Cairo from Sharm el Sheik for an interview which cost a lot of money, only to be told he was suspected of trying to emigrate to Britain and escape national service. You would think they would make sure he got on the plane to Britain."
Mr Sawy's consultant, Dr Elaine Clutterbuck, has written to the British embassy in Cairo in support of Ehab's visa application. She stated that Ealing Health Authority has given permission for Ehab's medical care to be paid for. Hammersmith hospital last night described Mr Sawy's need for a transplant as "important".
A foreign office spokesman said: "We are aware of the fact that Mr Sawy's son was turned down for a visa. Our paramount concern in these cases is an applicant's returnability to the country they are coming from. We were concerned about the military service, the fact he is not well-paid and whether there were sufficient grounds for his visit."
A spokesman for the British embassy in Cairo said last night: "Ehab should reapply to us."