Aldrich Ames, the CIA agent who spied for the Soviet Union and Russia in one of the most damaging intelligence breaches in US history, has died in a Maryland prison. He was 84.His death on Monday was confirmed by the Bureau of Prisons.

Ames is best known as an ex-CIA agent who spied on the US on behalf of the Soviet Union. Ames, along with his wife, Rosario Ames, was arrested in February 1994 and pleaded guilty without a trial to espionage and tax evasion. Aldrich was charged with espionage, and his wife with aiding and abetting his activities.

The couple pleaded guilty to their respective charges. Aldrich was sentenced to life without the possibility of parole, while Rosario got a little over five years.

Ames admitted to passing on information to Moscow for nearly a decade, including the identities of western agents behind the Iron Curtain, and says he was paid $2.5m by Russia. He was arrested In a jailhouse interview with the Washington Post the day before he was sentenced, Ames said he was motivated to spy by “financial troubles, immediate and continuing”.

He professed “profound shame and guilt” for “this betrayal of trust, done for the basest motives”, money to pay debts. But he downplayed the damage he caused, telling the court he did not believe he had “noticeably damaged” the United States or “noticeably aided” Moscow.

“These spy wars are a sideshow which have had no real impact on our significant security interests over the years,” he told the court, questioning the value that leaders of any country derived from vast networks of human spies around the globe.

Ames was working in the Soviet/Eastern European division at the CIA’s headquarters in Langley, Virginia, when he first approached the KGB, according to an FBI history of the case. He continued passing secrets to the Soviets while stationed in Rome for the CIA and after returning to Washington. Meanwhile, the US intelligence community was frantically trying to figure out why so many agents were getting discovered by Moscow.

In 2018, Ames’s name re-entered the public imagination by way of Ben Macintyre’s book The Spy and the Traitor, which detailed the rescue of a KGB colonel working for MI6 named Oleg Gordievsky from Moscow in 1985. Ames is the titular “traitor” because he tipped off Moscow to Gordievsky’s activities.