The man, one of two rejecting water as well as food, is one of 16 detained immigrants from five countries - Nigeria, Zaire, Romania, Algeria and Somalia - who have been on hunger strike for nearly four weeks.
The first inmate taken to hospital earlier this week, Nigerian Ejike Emenike, aged 30, has returned to the prison after receiving emergency rehydration treatment in Medway Hospital, Gillingham. He has now rejoined the hunger strike.
The prison hunger strikers claim that asylum seekers are being treated like criminals while their applications are processed. But Michael Howard, the Home Secretary, yesterday insisted that the law had to be applied firmly - with a proper system of controls.
"This is not least so that we can continue to have race relations which are the envy of most of the rest of the Western world," he said.
Mr Howard defended the Government's record on the treatment of asylum seekers as "fair, reasonable and generous".
Mr Emenike,a Pentecostalist pastor, has been in detention since last February. He fled Nigeria after being severely beaten in a police cell in Lagos for a sermon criticising the hanging of the dissident writer and activist Ken Saro-Wiwa.
The hunger strike, which began almost four weeks ago and originally involved 48 of the 180 asylum seekers at Rochester jail, has become a focus for organisations opposing Britain's immigration laws. More than 100 sympathisers staged a demonstration outside the prison walls yesterday.
n Another hunger strike continued yesterday - by anti-road campaigners demanding the release of details of the contract to build the A30 bypass. Jennifer Hall, 23, and Sarah Baker, 22, remanded in Eastwood Park prison, in Gloucestershire, and John Davies, 32, remanded in Exeter prison, are all refusing to eat.
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