Gary McKinnon, the UK citizen accused of hacking Nasa's computers and causing hundreds of thousands of pounds worth of damage, was taken ill as his appeal against extradition continued.
According to those close to McKinnon, he suffered heart palpitations on Wednesday. "The case has all become too much for him," a friend told ZDNet UK.
McKinnon is accused of breaking into 97 US computers and causing £700,000 of damage in 2001 and 2002. He admits accessing Nasa computers, as part of his search for evidence of extraterrestrial life, but denies deliberately causing any damage.
In McKinnon's absence, his defence lawyer told the High Court that his extradition should be blocked because the US authorities had offered him a shorter sentence in return for agreeing to extradition. Edmund Lawson, QC, claimed that this constituted an "improper approach" to McKinnon.
Representing the US authorities, Max Summers told the court that the US was not able to refute this claim immediately and would need an adjournment to consider it.
The case was adjourned on Wednesday afternoon, and the appeal judges will now deliberate on whether this new evidence can be considered.
If he loses his appeal, McKinnon may try and appeal to the European Court of Human Rights, although this may be blocked by the High Court.