The identity of Deep Throat - the man who leaked secrets to the Washington Post during the Watergate scandal has been confirmed.
Former FBI deputy chief Mark Felt, now 91, admitted in Vanity Fair magazine that he was "the guy they used to call Deep Throat." The FBI has not yet commented.
One of Nixon's counsels who served time in prison over the Watergate affair expressed surprise that Mr Felt had "done it alone", raising the question, often debated, of whether the informant could ever have been a single person.
What do you think about Mark Felt being Deep Throat? Are you surprised? Do you believe the news?
This debate is now closed. Read a selection of your comments below.
The following comments reflect the balance of opinion we have received so far:
I was disappointed when Mark Felt revealed his identity as Deep Throat. All these years I had been hoping Deep Throat was a politician, if only to show that somewhere out there was a Republican politician whose loyalty to county and rule of law superseded his loyalty to his party and president. There goes my last shred of youthful idealism.
Melissa, Evanston, USA
This man is no hero, if he were; he would have had the guts to identify himself at the time. I could never understand the US obsession with Watergate; to me it was a storm in a teacup, blown out of all proportion by a news media that were out to get Nixon from the start. People forget that in the 1972 election, Nixon was re-elected by a landslide, so he cannot have been that bad.
Good job, Mr. Felt. America needs more men willing to inform and play watchdog on the government, and it's a shame that such actions get painted in a bad light. In a democracy, it is the job of the people to keep the government in check.
Blake Murphy, Buffalo, NY, USA
I thank Mr Felt for his work to preserve the honour of the American government and the people it represents. Undisputedly he is a hero for us all to look up to. Simply a legend, which I am glad can be told sooner, rather than never. Thank you for breaking the silence and taking credit for your achievement.
Brandon, Santa Cruz, CA, USA
Hero? Hardly. A hero is someone who risks their life for others or for their country. He did neither. He hid in the shadows for 30 years, doing something that was just as illegal as those supposed criminals he was exposing. National security would cease to exist if everyone working for the FBI leaked information.
Sherry, Overland Park, KS USA
I had no idea who was Deep Throat and I am very glad he chose to reveal himself. Mr Felt carried his burden for a long time. I am looking forward to the next book by Woodward and Bernstein. It is interesting to compare the personalities of Nixon and Felt. One was paranoid and condemning while the other was caring and directing. Much credit goes to Bradley, Bernstein and Woodward.
The oddity in all this is that if Mr Felt had done what he did today, he would've been prosecuted. Nothing has changed. Nothing has been learned. If anything, the US government has only become more secretive and less accountable. Nixon is but a footnote. His legacy lives on in the abuse of power and a culture of lawlessness that pervades the government.
Tony, Ohio, USA
Thank you, Mr Felt. If the guardians of our country would take a lesson from your independent and courageous acts then maybe we would not have the current disgraceful leaders we have running our country into the ground today!
Paul, Gainesville, FL, USA
If Tom (UK) thinks Watergate was boring, he apparently was probably not born yet. What was exciting was the news media and a bi-partisan Congress were going after the president of the United States, not for political gain, but because it was the right thing to do. It could happen today, but neither the Congress nor the press have the guts anymore.
Dan Kerrigan, Joliet, IL USA
It is good for historians and the rest of us that the source of the inside information that fuelled the Watergate affair has finally been identified. Whatever Felt's motives, he served his country well by contributing to the exposure and subsequent resignation of, probably, the most corrupt and destructive US president of the last century.
Roy Stannard, Bangkok, Thailand
It is ironic, to say the least, as Mr Felt himself was pardoned by President Reagan for his own conviction for authorising breaking and entering. Is he a hero? I don't think so. I'm glad he did what he did, as bringing down Nixon for his crimes was a necessary evil, but I suspect he did it for his own personal career reasons and his hatred of Nixon rather than the benefit of the country.
Steve Mac, Boston MA, USA
Watergate is of interest to more than just a few elderly Americans (I'm 24, by the way)? This was the moment in our history when we, as a nation, stopped fully trusting our leaders. And so the identity of Deep Throat was one of the most intriguing mysteries of our time. I am glad to discover the identity, but am not satisfied - I have so many more questions! How wonderful it is that he revealed himself while still alive!
Vanessa, Connecticut, USA
The man is no hero. He violated his trust and the obligations of his position. His position did not grant him the right to hand over FBI information to the news media in the darkness of a parking garage instead of routing it through the chain of command at FBI. God help us if every law enforcement officer in the US had this privilege of decision.
George, Hamilton, MT, USA
Regardless of what exactly Mark Felt's motives were, the Nixon administration was corrupt and needed to be brought down. You can call him a turncoat, but Nixon and his gang were criminals.
Jennifer, Harrisburg, IL, USA
Thank you Mr Felt for having the integrity to uphold the law and stand up for what was right and just, when all around you everyone else was caving in the face of corruption. I hope there are people like you right now in positions of power in the world. Now, if we only had a Woodward and Bernstein to report the real news.
Diane Witt, Renton, WA, USA
It doesn't much matter what anyone else thinks except Americans. This man is not a hero. He should have taken this to his grave and kept his mouth shut. If he felt so strongly that he did the right thing, he should have come forward and identified himself when he first betrayed his job and leaked the information. But no, he was afraid because he knew what he was doing could land him in jail. What makes his crime less serious than the crime of those he exposed? Nothing.
Chris, Germantown, Maryland USA
The man is not a hero. He is coming forward now for money. Thirty years ago, his motive for leaking confidential FBI information was revenge for being passed over as chief. Although the Nixon White House needed cleaning, Mark Felt's motives were not honourable then and aren't honourable now. He and his family want to cash in before he dies. Bernstein and Woodward have also been waiting for him to die to cash in, looks like he stole their thunder.
Carol Wilson, Olympia, WA USA
If only our press today was a tenacious as Woodward and Bernstein. What would they find about the current administration? Mr Felt is a true American hero. Truth should always prevail over politics and bureaucracies.
Chuck L, Los Angeles, CA USA
If only someone privy to what was discussed in the meeting between George Bush and the British intelligence minister had exposed it at the time instead of two years into a war that never should have happened. Think of the lives that would have been saved! We need more Mark Felts in government and a media that will pay attention to them.
Joan Norman, Naperville, IL, US
Why should we believe this man? In my opinion Pat Buchanan is still the most likely source. Is it inconceivable that this is merely an attempt to block a move by Buchanan who was going to reveal himself as the "saviour of democracy" in the US, before putting himself forward for the next presidentials.
Darryl Jordan, Amsterdam, Netherlands
It's amazing that Deep Throat's identity has been kept a secret for all these years. Regardless of his motives, Mark Felt should be commended for assisting Woodward and Bernstein uncover the truth regarding the corrupt Nixon Administration. Where are the Deep Throats of today?
Andrea Quijano, New York City, NY, USA
Somebody was going to profit from this, and it might as well be his family. We all know that if the secret died with him, the only ones to make money would have been Woodward and Bernstein with another book.
Rich Sittema, Dallas, Texas
Watergate emboldened a biased media. In the past 4 years, the old media has repeatedly reported unsubstantiated, if not totally false, stories concerning President Bush. Deep Throat uncovered is merely today's media reliving its glory days, which are long gone.
He broke a code of ethics. I think it's only a political ploy by the Democrats to play up the story at this time. This event happened around 30 years ago and I cannot understand why all the hoopla and media hype in regard to who the heck "Deep Throat" is - he and his family seem to be fully enjoying the media attention as if this former FBI agent is a Hollywood celebrity.
If every person who had access to classified information divulged the information they felt should be made public then democracy would cease to exist.
Todd, Virginia, USA
If Mark Felt is Deep Throat, how did he know what we now all know? As assistant director in the FBI his immediate superior was a Nixon buddy and the Attorney General who was later incriminated would have been very close to both the director and his number two. It is surprising that not more people knew of the facts and did not come forward to the press.
I don't see what the fuss is all about. Indeed, it is unbelievable that journalists and others are still so engrossed in this affair. It is the victory of their politics, I suppose, that they brought down a conservative president. I am curious though, what motivated Felt to do what he did?
Jeremy, Atlanta, USA
I hope Deep Throats everywhere will weigh their conscience above discretion. Mr Felt performed an act of courage and totally in the public interest, for which he should be applauded by those who support democracy everywhere.
Andy Millward, Broxbourne, UK
Finally someone in our government with a conscience!
Aaron, Rochester, NY, USA
A weak point in the US constitutional system has been the limited ability of the Justice Department to independently investigate and prosecute wrongdoing in the executive branch. In a sense, that weakness was at the heart of the Watergate problem. I don't think Mr Felt's actions should be dismissed as tawdry only because he may have had reason to feel personally disgruntled (as well as professionally disgusted).
B Larimer, Denver, CO USA
I cannot believe that some people are so complacent about the revelation of Deep Throat and the whole Watergate affair. How can they say that it doesn't matter or have any importance? This is the man who helped bring down a corrupt presidency and he should be applauded for doing so. We need more people like him now that don't let those with power get away with whatever they want.
Amy, Essex, England
Jonathan Aitken, Nixon's biographer, makes the point that Felt couldn't have been the only source, as he couldn't have known about the missing 18 minutes on the infamous tapes. He was one source, maybe, but not the only one.
John, London UK
I think it is an injustice and simple minded to say Felt was a disgruntled employee so he "blew the whistle". To date he has not gained much from doing so. What is wrong with acknowledging a real hero when we see one?
Anonymous, New York, US
I've heard the term "hero" used in association with Deep Throat. A hero risks his life for others. Whether Mark Felt is the real Deep Throat, Deep Throat is no hero. Whether it was the correct thing to do or not is questionable. Heroic? No way!
Bob Michaels, Syracuse, USA
For those who say it does not matter: I was a little girl and not in the country when Nixon was ready to dissolve Congress; when his administration had put literally anyone suspected of not being "one of the boys" lives in danger. But I think that what Mark Felt did matters tremendously. I don't know if he was a hero or if he should get a medal; I do know that he was one man who looked around, said this is wrong, refused to follow orders, and (perhaps) saved the Republic.
Inna Tysoe, Sacramento, CA, USA
One of the great political mysteries of the second half of the 20th Century has finally been resolved. It is a credit to Woodward and Bernstein that they have kept silent for 33 years. What a shame that no genuine whistle blowing is either allowed or encouraged in 21st Century Britain or the US, as there are certainly as many issues (e.g. Iraq) which could benefit from men such as Mr Felt! Congratulations to him and I hope that this helps allay the current revisionist approach to Nixon and his crimes.
Andrew M, Munich, Germany
Mark Felt acting as a leak to Woodward and Bernstein alone would most likely not have been successful in bringing down the Nixon presidency. Nixon brought himself down with the proof of his crimes in the irrefutable evidence. The tapes were his own self incrimination, which he failed to destroy.
JT, Gary, Indiana, USA
I am relieved to know that there are people like Mr Felt, who took great risk in taking on a powerful and corrupt US president, in order that the integrity of the US presidency is preserved. His example, and the example of Washington Post reporters Woodward and Bernstein in keeping their sources a secret, is a valuable lesson on the critical role the press plays in preserving the integrity of our government - when Congress and the US Supreme Court fail to keep the executive branch in check, the press must not.
Eric Nakano, Washington, DC, USA
This is non-event for most everyone except the rapidly aging professional Nixon haters. Like veterans who can't seem to shed their worn out, ill-fitting uniforms, they keep reliving and re-enacting Watergate, longing for the good old days when they could take down a president.
Peter Plotts, Austin, Texas
An interesting historical footnote, but does anyone really care? Watergate is now just part of our history, not the burning issue that shook the entire country (and our faith in government) in the 1970s.
Brian, Kansas City, USA
The lack of outrage by the American people is shameful, everyone seems lost in the drama of this great revelation without a thought to the gravity of its implications.
Bart Woolery, Santa Barbara, USA
How anti-climactic. It was better not knowing.
Of course Mark Felt was right to reveal the truth. Politicians are dishonest and the public needs whistleblowers to safeguard the public interest and prick the pretentiousness of the so-called political elite. Give him a Congressional Medal for bravery.
P Thomas, Merseyside
My reaction is that if today Watergate happened again nobody will be shock in US: they abandoned their freedom for a so-called security!
N Gibert, Paris, France
We still put too much trust in our politicians and allow them to keep too many secrets. Perhaps a reward should be given to Deep Throat to indicate that misdeeds by people in positions of trust will not be tolerated in future.
John Ley, High Wycombe, Bucks
Seeing the gentleman on TV, he looks to me like a guy who is happy to have some attention paid to him. I was born after Watergate, so quite honestly, a re-run of the Beatles appearing on Ed Sullivan means more to me than this.
Wes, California, US
Whatever his real motives were for revealing the scandal, it is easy to assume that being passed over for the FBI's top job prompted Mark Felt to take the action he did. We may never know why he was passed over, but maybe it was thought that he would blow the whistle on any future political scandal were he not reigned in, almost in anticipation of something like Watergate occurring.
David, York, England
Where are the deep throats of today? Would the US media even pay attention if they came forward?
Lane Brisendine, Birmingham, Alabama, US
I'm sure this is of some interest to a few elderly Americans. Watergate was pretty boring stuff at the time and has not got any more exciting with age. The only thing even remotely interesting about it was that it elevated to High Office probably the most bland and innocuous US president ever - Gerald Ford.
We certainly live in interesting times. If Watergate would happen now, no-one would really care, as worse things have happened since then. A presidency brought down by members of the media and their so-called source. If Mr Felt was Deep Throat he was also a highly paid civil servant working for a government entity engaged in law enforcement oversight.
Because of his position, Mr Felt was privy to highly sensitive information and he abused that position. I do have a problem with him leaking that information which he had absolutely no right to do.
D Stewart, North Carolina, USA
Why publish in Vanity Fair and not Washington Post? Glossy photo?
At last, as a young man in the seventies the two great mysteries were Deep Throat and Lord Lucan. One down, one to go
BJ Ruddell, Perth, Australia
Now that everyone knows Felt is DT, there are a lot of experts with a lot of egg on their faces: John Dean first thought it was Al Haig (as did Len Colodny), then changed his mind to Jonathan Rose (Jonathan who?). Leonard Garment concluded in his book In Search of DT that it was John Sears. And, last but not least, Bill Gaines decided that it had to be Fred Fielding (Dean's assistant, and member of the 9/11 commission). I wonder how they will react to this news.
Henk Verdru, Heule, Belgium
I had my money on Fred Fielding, plus they always seemed to talk of Deep Throat as somebody who worked in the executive branch. Still don't understand how he (Mr Felt) was able to point Woodward and Bernstein in the right direction e.g. to follow the money. But fair play to him for exposing Nixon, Halderman, Mitchell etc.
Scott Hayes, Birmingham, England
My money was on Kissinger, what a let down!
PM, NYC, US
Actually, it is kind of scary. How did this man have the inside information?
George, Tokyo, Japan
If Mr Felt was instrumental in getting rid of Nixon then surely a Congressional Medal of Honour is the least this man can expect!
Alasdair Binns, Glasgow, Scotland
This should put an end to an era that marked the turning point in American history. Nixon's failing was to put people around him who lusted after power, and some of them still profess to be against America. So, Felt is no hero, but also a former member of the US government who also sought power through illegal means.
A hero saves something or someone from a worse situation, and does this without the forethought of reward. Whether or not this puts an end to the mystery around Watergate will depend on how much is believed by the public.
Walter, Hong Kong
I had a good feeling that they'd say who it was sometime soon. I'm glad he went forward before he died - it makes the whole thing a lot easier to take in. I think we were all surprised it was Mark Felt because none of us ever expected it.
Omar, Charleston, WV, USA
It seems fairly credible. I think it's time someone got the chance to give him an interview so that we can find out as much as possible about one of the most interesting events of modern history.
John Kelly, Cambridge, UK
If it is him then he should be congratulated as he got rid of a devious criminal who was in charge the most powerful country in the world.
Adrian Cannon, Edinburgh, Scotland
Mr Mark Felt did a great service to his country. His impressive act of courage ensured that, in the end, justice was done.
Olav Grinde, Bergen, Norway
That Deep Throat is a former deputy chief of the FBI is not surprising - the leak had to be at that level. Was he correct in revealing this information? History shows that while he may not have been entirely in line with FBI guidelines, in the long term what he did was justified and the USA got rid of an extremely unpleasant president.
James Jardine, Jo Pessoa, Brazil
Good for him. Government informers should be give the highest honours. He demonstrates that you don't have to love the president to love the country.
Mark, Brisbane, Australia
Why it was kept a secret for so long is amazing. A man of morals that people with any power today could learn from.
Lee W, Dagenham
People say that the job of the two journalists showed the good work of democracy. But then why were they scared to reveal their source. They thought he would be killed. This shows the weakness of democracy, and the strength of the USA to the normal people
Mohammad Javad Malayeri, Vienna, Austria
Another example of someone who, rather than expose himself by telling the truth publicly, sneaks around and then when considering it safe to so do, takes the credit. He is not a hero. Having said that, such are the powers of state he may have had an accident at the time!
David, Manchester, UK
I feel he did as much harm as good and was certainly no hero. Yes, Nixon was involved in the Watergate scandal but he also achieved many good things such as ending the Vietnam War and recognising mainland China. Also by leading to the fall of Nixon, Mark Felt paved the way for the Presidency of Jimmy Carter, a disaster for the USA and to blame for many of the problems in the Middle East today such as in Iraq.
Steve Foley, Reading, England
The whole thing is history and it does not make much difference 30 years on if Mark Felt was Deep Throat or not.
Richard, London, UK
After all the mystery, conspiracy theories, hours of panel discussions, we find that it was just another disgruntled American employee!
David, St Catharine's, Ontario