Mark Felt, the mysterious "Deep Throat" whose leaks on the Watergate scandal helped bring down President Nixon, has died at the age of 95.

Felt died yesterday at a hospice near his home in Santa Rosa, California. His daughter, Joan Felt, told the Washington Post that he fell asleep after eating a big breakfast and "slipped away".

Felt was No 2 at the FBI when he started passing information on a June 1972 break-in at the Democratic National Committee in the Watergate complex to the Washington Post reporter Bob Woodward, whom he had first met in 1970.

Using the tradecraft he picked up on the FBI's Espionage Section in the Second World War, Felt insisted on strict counter-surveillance measures to protect his identity.

Times Archive, 1974: Backroom boys of Watergate

Bernstein and Woodward identify their main source as 'Deep Throat', who prosecutors believe was Mark Felt Jr, a deputy associate director of the FBI

• Guessing the identity of 'Deep Throat', 1976

• Archive Topic: Watergate and the Fall of Nixon

Related Links

• The Times obituary: Mark Felt

• Woodward - why I kept Deep Throat secret

• Watergate’s invisible man strikes back

Multimedia

• ARCHIVE: Nixon and Watergate

• Watergate

• Comment Central: Deep Throat reader

If Woodward wanted a meeting he would move a flowerpot with a red flag on the balcony of his apartment. If Felt had information to divulge he would leave a message on page 20 of Woodward's copy of The New York Times which he had delivered every morning.

The two men would then meet – usually at 2am – on the bottom floor of an underground car park across town.

"I suspect in his mind I was his agent," Woodward later wrote. "He beat into my head: secrecy at all cost, no loose talk, no indication to anyone that such a secret source existed."

With his reporting partner Carl Bernstein, Woodward produced a series of exclusive front-page reports that gradually edged the story closer to Richard Nixon's Oval Office until in August 1974 Nixon became the first US president ever to resign in disgrace.

Their efforts won the Post a Pulitzer Prize, spawned a major Hollywood movie and inspired a generation of investigative journalists around the world.

But no-one except for Felt, Woodward, Bernstein and Ben Bradlee, the Post editor, knew for sure the identity of the most famous anonymous source in history, dubbed "Deep Throat" after a famous 1972 hardcore porn film.

Indeed, Bernstein himself did not meet Felt until he was introduced to him by Woodward last month, three years after Felt's identity was finally revealed by the magazine Vanity Fair. Woodward, Bernstein and Bradlee had all promised not to reveal his identity while he was still alive.

Felt's motivations for helping to bring down Nixon are still unclear, although he was clearly embittered at having been passed over for the top job when the FBI's founding director, J. Edgar Hoover, died in May 1972, just a month before the Watergate break-in. He was also, Woodward wrote, angered at what he saw as the corruption of the Nixon White House.

"Felt believed he was protecting the bureau by finding a way, clandestine as it was, to push some of the information from the FBI interviews and files out to the public, to help build public and political pressure to make Nixon and his people answerable," Woodward wrote.

"He had nothing but contempt for the Nixon White House and their efforts to manipulate the bureau for political reasons."

Although Nixon himself received a pardon from his successor, Gerald Ford, more than 30 officials were convicted or pleaded guilty over the scandal, including the Attorney General John Mitchell, who served 19 months for conspiracy, obstruction of justice and perjury.

Felt, an imposing figure with slickly combed grey hair, repeatedly denied he was Deep Throat, even though his position at the FBI made him an obvious candidate, and Nixon himself suspected him of leaking to the media.

A character patterned on Felt showed up in the book and subsequent feature film "All The President’s Men," an account by Bernstein and Woodward of their Watergate reporting in which the reporters parts of were played by Robert Redford and Dustin Hoffman. Played by Hal Holbrooke, the Deep Throat" character was seen in the shadows.

Born on August 17, 1913 in Twin Falls, Idaho, Felt came to Washington as a Capitol Hill staff member and later worked at the Federal Trade Commission before joining the FBI in 1942. After serving in the bureau’s espionage section during the War he later worked in various field offices and oversaw some of the FBI’s early investigations into organised crime.

Felt was appointed deputy associate director, the No 3 job at the FBI, in 1971, and was disappointed when Nixon named L. Patrick Gray to head the agency after the death of its longtime chief, J. Edgar Hoover, in 1972.

Felt was convicted in 1980 of authorising illegal break-ins at five homes in New York and New Jersey as part of the FBI’s pursuit of the radical Weather Underground group. He was fined $5,000 and then pardoned by President Reagan in 1981. Felt and his wife Audrey, who died in 1984, had two children.

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