JUDY WOODRUFF: Almost 20
years, American embassies
in Africa were attacked
by al-Qaida, making
the terror group's
leader, Osama bin Laden,
an infamous household
name, three years before
the horror of
September 11, 2001.
During that period, MI6,
which is the British
foreign intelligence
service, had an agent
inside al-Qaida.
He has now unmasked himself.
And he spoke with Jonathan
Rugman of Independent
Television News.
JONATHAN RUGMAN: He
calls himself Aimen Dean.
For eight years, he worked
for MI6 as a double agent,
mostly inside al-Qaida.
And now one of the West's most
important spies has broken
cover to tell his story.
AIMEN DEAN, Former Undercover
Agent: If you spend eight years
under cover, at some point,
basically, you will start
to feel the effects.
JONATHAN RUGMAN: In 1996,
Aimen Dean underwent al-Qaida
training in Afghanistan.
The teenager from
Bahrain already fought
as a jihadi in Bosnia.
Now he swore an oath of
allegiance to Osama bin Laden.
Did he impress you?
You write that he was
tall, he was softly spoken.
AIMEN DEAN: Absolutely, someone
who was -- who could have had
a luxury life in Saudi Arabia,
someone basically who could
have had an easy life, and yet
he gave all that up in order
to serve a cause
bigger than him.
JONATHAN RUGMAN: Al-Qaida's
bombings of U.S. embassies in
Kenya and Tanzania left hundreds
dead and Aimen Dean
outraged by the carnage.
Then three years later,
September the 11th,
almost 3,000 people
killed, and Dean had known
one of the hijackers.
By now, though, he'd moved
to London, using the need for
medical treatment as cover to
become a British spy.
Your job was to carry radios
and phones into Afghanistan that
enclosed MI6 bugging devices.
Was that it?
AIMEN DEAN: Well,
more than that.
My job was basically to
report on locations of
camps, the new training
methods, the individuals
coming in and out, and also
at the same time keeping up
with al-Qaida's WMD program at
the time.
JONATHAN RUGMAN: But if you
were doing all that, why did
an attack like September the
11th happen?
AIMEN DEAN: If you wanted to
stop 9/11, you have to have at
least 12 spies inside al-Qaida,
and each one inside one of
the different departments.
Only then, you could
have stopped it.
JONATHAN RUGMAN: What was
your biggest intelligence
coup, as far as you're
concerned, in terms
of what you managed to prevent?
AIMEN DEAN: Well,
there were several.
I mean, there was a plot to
attack the New York subway with
chemical weapons, a chemical
device that was invented
during my time actually in that
specialist lab in Afghanistan.
And I was reporting
on it regularly to the
U.K. secret services.
JONATHAN RUGMAN: He never
visited MI6 headquarters.
Before any meeting, he would
call his handlers from a series
of phone boxes to be given a
rendezvous and to allow
spotters from MI5 to check
he wasn't being followed.
His spying career ending
in 2006 during a boat
ride on holiday in Paris.
He was told the Americans
had leaked details of his
identity to a journalist.
MI6 ordered him back to London.
Do you have any lasting regret
that you betrayed people whom
you had become friends with?
AIMEN DEAN: No.
I did not betray a state.
I betrayed a bunch of
criminals, as simple that.
JONATHAN RUGMAN: Aimen Dean
lives quietly somewhere in the
British Isles, his code name,
Lawrence, as in Lawrence of
Arabia, an identity he left
behind over a decade ago.
JUDY WOODRUFF: That
was Jonathan Rugman of
Independent Television News.