In the film Mark Felt: The Man Who Brought Down the White House, Liam Neeson stars as the title figure, the FBI agent who used the nickname "Deep Throat" as he leaked top secret information to the press during the Watergate scandal in the early 1970s, leading to the resignation of President Richard Nixon.

Liam Neeson at the premiere of 'Mark Felt: The Man Who Brought Down the White House'Liam Neeson at the premiere of 'Mark Felt: The Man Who Brought Down the White House'

In taking the role, Neeson particularly liked the approach writer-director Peter Landesman (Concussion) took to the events. "Details are very, very important to him," Neeson says. "Our story of Watergate is quite an intimate story. It's a small-budget film. It's worthy, and it shows something of Mark Felt's certainly bureaucratic life on display and something of his intimate life with his wife and his child."

For Neeson, the role was an intriguingly complex one. "I think he was conflicted," he says. "Very, very much, he definitely was! It wasn't a black and white thing, 'I've got to stand up and defend the constitution.' He certainly felt he wanted to defend what the FBI stood for, and yet he was also letting it down in one sense because he was supplying bits of information to the press that eventually led to Nixon resigning. This was an incredibly important time in Western history when a president and his team committed criminal acts and the freedom of the press was proven to work."

Watch the trailer for 'Mark Felt: The Man Who Brought Down the White House' here:

In dramatising a turbulent period in American politics, the cast and crew didn't really know how relevant the material would be today. "We shot the movie in March-April 2016, so we knew that Mr Trump was running," Neeson says. "But now that he's been elected we're saying, 'Oh my gosh, there's lots of similarities here that seem to be unfolding every day.' But yeah, history does have a habit of repeating itself and our elected leaders have to be held accountable."

Neeson says the similarities go even further than that: "Nixon felt, 'Let's circle the wagons!' Everybody was an enemy that wasn't on his side. We're certainly seeing that with President Twitter in Chief. If you're not with me, you're against me." 

The 65-year-old actor, who has had a second career recently as an action hero, sees what Felt did as patriotism. "I think it's being able to stand up and remind this country what it's doing wrong," Neeson says.

More: Liam Neeson on rumours that he's 'retired' from action

And even though the media keeps saying he has retired from action movies, Neeson laughs off the idea. "It's not true," he says. "I'm going to be doing action movies until they bury me in the ground. I'm unretired."