Doha, Qatar - Barack Obama's failure to shutter Guantanamo Bay was a stain on his legacy as US president, according to Shaker Aamer, a Saudi-born UK resident held at the infamous US detention centre for nearly 14 years without trial.

Aamer was arrested in Afghanistan in 2001, but was never charged with a crime. He was released from the Cuba-based prison in October 2015 and has since lived with his wife and four children in Britain.

Despite Obama's January 2009 executive order to close Guantanamo, he failed to do so throughout his eight years of presidency.

Of the 240 prisoners who were there when Obama took office in 2009, 55 are still in Guantanamo, according to Human Rights First.

As many as 19 have been cleared for release, while a mere three individuals from the remaining detainees have been convicted by a military commission.

Overall, more than 780 people have been held in Guantanamo, and the prisoner population peaked at 684 people in June 2003.

President-elect Donald Trump, who will take office on January 20, has already vowed to keep the prison open and lock up "more bad dudes".

Al Jazeera spoke to Aamer about Obama's legacy, the effect of hunger strikes and his life after his release.

Al Jazeera: Will the US shut down Guantanamo Bay?

Shaker Aamer: Can they shut down Guantanamo? Yes. But first of all, people have to understand why they want to keep Guantanamo open. There's more to it than just politics or safety. If they close Guantanamo, what will tell the world about who's to blame for these 15 years when they put [away] all these people who didn't belong there?

It's just about explaining to the people. We are talking about one of the most sophisticated intelligence services in the world. Guantanamo proved to the entire world that the CIA operates outside [the rules] of the [US] government. It's a government inside a government, and they operate outside the law. Who's willing to answer all these questions? Are they willing to answer them? No, they're not.

READ MORE: What's next for Guantanamo?

People have to ask why it cannot be closed. It's about responsibilities and opening the books, answering questions to the whole world.

First of all, they have to [answer these questions] to the Americans. The impact of what happened on Americans was great, on the way they live and their freedoms. And everything we suffered was because of "national security". I couldn't receive letters from my own kids because of "national security". I couldn't speak freely with my lawyer because of "national security".

After all this, do you think they're going to close Guantanamo and then tell the world they've got only a handful of people that "we're trying to put on trial for the past 10 years and until now we cannot succeed"? Can the world accept that? No. That's why this scarecrow that is Guantanamo has to stay.

Al Jazeera: Will you continue to fight for the closure of Guantanamo?

Aamer: It's about our futures. We are still suffering. They [governments] refuse to talk about it now. For [governments], it's normal because they didn't lose anything. But for me, I lost 14 years and I won't sacrifice them without benefiting today and tomorrow - and I'm not talking about personal compensation. They compensated us [financially], but without saying, "sorry".

It's a lot bigger than me. It's not just because of the detainees. We are talking about a whole government, a whole system. They [the US government] lied to their own people just to let their soldiers accept torturing us. Can you imagine that they had to go to classes and show them movies about us? They had to make [guards and soldiers] believe they were defending freedom. For [a soldier] to accept all this, they had to brainwash them. Now we have to reverse everything to let them know that we are human beings and we haven't done anything.

Al Jazeera: You have a reputation as having been a key protest leader while you were in Guantanamo Bay. How important were the hunger strikes and other protests within the prison walls?

Aamer: When someone launches a hunger strike, it means he is willing to lose his life for the cause. It is a peaceful tactic. They told the world we were trying to kill ourselves to serve al-Qaeda. It's amazing how they twisted logic.

They were so brutal when they dealt with us [on hunger strike]. But a hunger strike was our peaceful means of telling the world: "Listen, if I'm guilty, put me on trial. If I'm innocent, send me home". We were hunger striking to gain some human rights. I swear to God, they treated us as less than cockroaches.

READ MORE: Guantanamo torture victims should be allowed UN visit

Some of the guards would break down. Not once, not twice - 10, 20, 30 times. It's beautiful when you see this soldier become your friend; when they sacrifice their own job, their income, for you. Some of them refused to participate [in force-feeding], they were sent back from Guantanamo.

Even though the US denies it, the hunger strike was effective. We gained some control. We changed the whole equation because of hunger strikes.

Al Jazeera: What has life been like since your release?

Aamer: I have no restrictions for me in any way - not written. But my phone is tapped; my house is being watched; there are cameras in front of my house all the time.

My lawyer advised me to stay away from overseas phone calls. I refuse to talk to anybody because I'm worried about my family and my kids. I don't want to do anything, even go back for questioning. My wife is still not ready to take any more pressure or shock. It's so sad.

At the same time, my wife worries every time there is a knock on the door. People in the UK are going to jail because they one time knew someone who is in Syria now. Imagine if I receive a phone call from someone who was in Guantanamo right now? Definitely, they are going to come knock on my door.

That's why I'm free, but I'm not free. I'm being watched.

When I came out, I found a different family, a different life, different kids. My kids are grown up. To build a strong relationship with them is not easy. It is hard. They are my kids, but they are not my kids. They are very good kids, very educated, very smart. They still see me as a little bit of a stranger.

Al Jazeera: It appears that Obama's final presidential term will expire without the closure of Guantanamo Bay. What do you think that says about his legacy?

Aamer: I remember when Obama received the Nobel Peace Prize [in 2009]. It was sad. I told [my lawyer], if people like Obama get this prize, it means nothing. Where is the peace he's implementing? At that time, we were roughly 300-something people [in Guantanamo].

What peace did he bring to the world? The damage he did is worse than [former US President] George Bush. If Obama can get this prize, it's just an insult. That prize is nothing. It's just a decoration.

For Obama, he wants to close it. I have no doubt, but I think he's too much of a coward. You cannot be a hero without being willing to sacrifice. He proved he's the biggest liar; he proved he's not a leader. The most basic thing he could have done is close Guantanamo. He could have brought so much [respect] back to America.

Follow Patrick Strickland on Twitter: @P_Strickland_