Sabeel Ahmed, of Liverpool, was charged with having information that could prevent an act of terrorism, the Metropolitan Police said in a news release.
Ahmed is the third person to be charged in connection with the alleged plot in London and Glasgow. His brother, Kafeel, is believed to have set himself on fire after crashing into the airport and is in a Scottish hospital with critical burns.
Muhammad Haneef, 27, a distant cousin who once shared a house with the brothers in Britain, was charged Saturday in Brisbane, Australia, with supporting a terrorist group. Bilal Abdullah, a 27-year-old Iraqi doctor, was charged last week by British police with conspiring to set off explosions.
Australian police charged Haneef with providing support to the bomb plot by giving his SIM card to Sabeel and Kafeel Ahmed when he left Britain for Australia in July 2006. Haneef faces a maximum of 15 years in prison if convicted.
British police tracked a SIM card found on one of the men accused in the failed bomb attacks to Haneef, and alerted their Australian counterparts. Haneef was arrested July 2 while trying to leave the eastern city of Brisbane for India on a one-way ticket.
Prosecutor Clive Porritt said Haneef would have known about the Ahmed brothers' alleged links to terrorism.
"These are people who he lived with, may have worked with, and certainly associated with," Porritt told the Brisbane Magistrates Court during a daylong bail hearing.
But defense lawyer Stephen Keim said Haneef only left the SIM card with Sabeel Ahmed so his cousin could take advantage of a special deal on his mobile phone plan.
"For some reason he should have been aware that something was going to happen when the rest of the world didn't," Keim said. "It is not suggested that he is anything other than a foolish dupe who should have been more suspicious."
Eight people were detained immediately after the botched attacks; one of them, the only woman, was freed on Thursday.
It was not immediately clear whether the SIM card was used in the foiled attacks.
Australian Magistrate Jacqui Payne adjourned her decision on whether to grant Haneef bail until Monday.
Prosecutors have opposed bail for Haneef, saying he could flee the country if released.
Porritt said Haneef made a "flurry" of phone calls to India on the day of his intended departure, including one to his brother who informed him police had linked him to the bomb plot.
But Haneef says he was rushing back to India to see his wife and newborn daughter, born June 26, and that he planned to purchase his return ticket in India.
Keim said it would be impossible for his client to leave the country because he has surrendered his passport and his photograph has been plastered on newspapers and television reports for the past two weeks.
"Whatever flight risk he represented two weeks ago, he doesn't represent now," Keim said.
Prime Minister John Howard urged caution in Haneef's case, saying he was still entitled to the presumption of innocence.
The case emerged June 29, when two cars packed with gas cylinders and nails were discovered in London's entertainment district. The next day, the flaming Jeep smashed into security barriers at the main terminal at Glasgow airport.
Some of the eight detained worked together as colleagues at hospitals in England and Scotland, and experts and officials say the evidence points to the plot being hatched after they met in Britain, rather than overseas.