The doctor at the centre of a political storm over the force-feeding of Guantanamo Bay inmates has defended the practice.

Omar Deghayes, a 36-year-old law graduate from Saltdean, is believed to be one of more than 80 inmates at the US detention camp being fed through tubes forced up their noses and into their stomachs while they are tied down.

John Edmondson's admission the practice was taking place has sparked a torrent of criticism from human rights groups, doctors and lawyers, who say it is against international medical ethical codes to feed patients against their will.

Dr Edmondson said according to World Medical Association treaties, force-feeding is permitted when detainees cannot make "unencumbered and informed" decisions with their families about going on hunger strike.

In a letter to British consultant neurologist David Nicholl, an outspoken critic of force-feeding, he said: "I do not believe what I am doing is in contravention of agreed international legal and ethical standards.

"In fact what I am doing is providing the best possible medical care."

But Dr Nicholl pointed to International Red Cross guidelines, which state: "Doctors should never be party to actual coercive feeding. Such actions can be considered a form of torture and under no circumstances should doctors participate in them on the pretext of saving the hunger striker's life."

Dr Nicholl said prisoners were being prevented from making informed decisions with their family about whether to go on hunger strike because the US government had refused relatives access.

London solicitors Allen and Overy, who represent some of the hunger strikers, have lodged a court action to be heard tomorrow in California, where Dr Edmondson is registered to practise.

They are asking that the state medical ethics board investigate him for "unprofessional conduct".

In a sworn affidavit in response to legal action, Dr Edmondson admitted force-feeding was painful and routinely caused bleeding and nausea.

Clive Stafford-Smith, a human rights lawyer who represents Mr Deghayes and more than 40 other Guantanamo inmates, said: "All the Guantanamo prisoners are suffering horribly and no doctor should play a role in ensuring they have no form of redress."