The light in his cell there is never turned off and he has to speak to his lawyers on a telephone through a thick plastic window.
In a bail application filed with the court, seen by The Daily Telegraph, the defence said Tappin lived with his wife on a combined pension of $2,000 a month and did not have the assets or desire to flee.
It said: "Mr Tappin is 65 years of age, walks with a cane, and cannot seriously be viewed as a danger to anyone."
Tappin's US lawyer Kent Schaffer painted a picture of a proud Englishman whose life revolved around his golf club responsibilities.
He also submitted character references from his wife and two children, the chairman of the West Kent Golf Club, the president of a diabetes charity and a school headmaster friend in Croydon. Golfing friends described him a "perfect gentleman" and "excellent company."
Tappin's wife Elaine wrote to the judge: "He has been a loving caring and constant husband to me and a devoted father to our children."
His son Neil, deputy editor of Golf Monthly, wrote: "He is a man I have looked up to all my life, not just because he is my father but because he is a man of genuine moral integrity."
The prosecution called Special Agent Ron Marcell, of the US Department of Homeland Security. He described how agents had established a bogus company, Mercury Global, to catch arms dealers.
Tappin was said to have tried to obtain 50 Eagle Picher batteries, a key component for Hawk surface-to-air missiles, through the fake firm intending to export them to Iran in violation of an arms embargo.
They were to cost $5,000 each and he planned to sell them to Iran for $14,000, the agent claimed. It was alleged that Tappin would have made a personal profit of $150,000.
Special Agent Marcell said Tappin made a series of payments from a Barclays bank account in London. The funds worth $70,000 had since been seized.
He also accused Tappin of planning to falsely label the batteries as for use in buoys and navigational equipment. The defence argue that Tappin genuinely believed the batteries were for use in the car industry.
But Special Agent Marcell said: "These batteries were very strong and had a very short lifespan. They were for use in a missile that's going to explode afterwards. They last only 90 seconds."
He said a series of other deals were also investigated, including the shipment of a "clean room" from California destined for Iran, and Yig filters used in communications monitoring. There was also a deal involving a "continuous rotation gimbal" which had been designated as "controlled technology" by the US, he said.
Prosecutor Greg McDonald said Tappin made numerous visits to the UAE which was a "notorious point for illegal shipments."
Mr McDonald added: "He might have character letters from the golf club but he's not going to get such glowing letters from those people shot down on planes, who were victims of these weapons. These people are screaming and crying that something be done to stop that sort of shipment."
Mr McDonald also suggested that if the condition of Tappin's wife, who suffers from chronic Churg-Strauss Syndrome, worsened then he might be more likely to flee.
The prosecutor said: "If she passes there is no incentive for him to return to the UK. Then it's no holds barred, he can get another passport and be gone. A mile from this court he's free in Mexico. All he needs to do is liquidate that $1.5 million home in the UK and he's off and running." Mr Schaffer said that argument was "absurd."