A Briton released from the U.S. military base at Guantanamo Bay (search), Cuba, said he was beaten, humiliated and interrogated for up to 12 hours at a time during two years' detention.

In a newspaper interview headlined "My Hell in Camp X-Ray," Jamal al-Harith said guards known as the Extreme Reaction Force (search) "waded into inmates in full riot gear, raining blows on them" as punishment.

The water and food was foul at Guantanamo, and sometimes as punishment, water taps in the cells would be turned off, al-Harith, 37, said in the interview, which was published Friday in the Daily Mirror.

The U.S. military repeatedly has denied that Guantanamo prisoners have been mistreated. The U.S. government says the roughly 640 prisoners are at Guantanamo because of suspicions they have links to Afghanistan's fallen Taliban (search) regime or the Al Qaeda (search) terror network.

Al-Harith arrived in Britain Tuesday night on a military flight with four other Britons freed from Guantanamo.

"He has been detained as an innocent person for a period of two years. He has been treated in a cruel, inhumane and degrading manner," his lawyer, Robert Lizar, told reporters.

He was regularly interrogated by FBI and CIA agents, and later Britain's MI5 intelligence agency, the newspaper said.

"They would shut off the water before prayers so we couldn't wash ourselves according to our religion," said al-Harith, 37, a convert to Islam. "We were only allowed a shower once a week at the beginning, and none at all in solitary confinement. This was tough because you are supposed to be clean when you pray."

"The whole point of Guantanamo was to get to you psychologically. The beatings were not nearly as bad as the psychological torture," al-Harith told the paper.

The families of the returnees have said they were mistakenly caught up in the U.S. war on terrorism.

Al-Harith describes a stay in an isolation unit known as an ISO, where those accused of misbehaving were kept in solitary confinement with just a mat and towel.

The newspaper also carried an account of what led to al-Harith's arrest.

The paper said al-Harith went to Pakistan weeks after the Sept. 11, 2001, attacks on the United States to learn about Muslim culture. Al-Harith was in Quetta near the Afghan border when the U.S. bombings against the Taliban began. He paid a driver to take him to Turkey, but was stopped in Afghanistan by an armed gang who accused him of being a spy after they saw his British passport and jailed him, according to the newspaper.

After the Taliban fell, he stayed with the Red Cross in Kandahar arranging to go home but was picked up by the Americans and interrogated. He was finally sent to Guantanamo Bay, the newspaper said.

Al-Harith said he arrived at the U.S. military detention center in Cuba on Feb. 11, 2002.

"I tried not to think about my family for two years because it hurt so much," the paper quoted him as saying. "I tried to contain everything. It was very difficult, but I survived — and I survived well."

The Mirror said al-Harith was divorced and has three children ages 3, 4 and 8.

Britain and the United States are continuing discussions about the remaining four Britons at the camp. Britain has insisted its nationals either receive fair trials or be returned home.