This laborious and solemn Nixon-era drama about the man who was “Deep Throat” gets off to a clumsy start with the title. He brought down the White House’s occupant, not the White House, and perhaps it’s worth noting that this was possible because a sizeable number of Republicans were prepared to think independently and act against the president. In 2018, the current incumbent can luxuriate in the knowledge that there is no immediate danger on that front, although this film’s depiction of a troublesome FBI is nonetheless relevant.

Liam Neeson – ramrod straight in a heavy business suit, with hairpiece and gravelly whisper – plays FBI deputy director Mark Felt, who fed information to the press, and particularly the Washington Post’s Carl Bernstein and Bob Woodward, about who knew what and when about the Watergate break-in. (He outed himself as the informant in 2005.) And why? Was he a closet pinko? Of course not – although he was a registered Democrat who went over to Reagan in the 1980s. Felt was a loyal bureau man who was convicted in 1980 of ordering break-ins – burgling the homes of suspected members of the Weather Underground, thus violating their civil rights. So were his activities down to pure petulance at being passed over for the top FBI job when its monarchical founder J Edgar Hoover died? Perhaps. This film, however, rather fudges that issue by simply making Felt furious at the new top man’s readiness to be a lapdog for the Nixon White House, apparently willing to whitewash Watergate.

Director Peter Landesman made the underrated JFK-assassination film Parkland, which stayed away from far-fetched theories, but this film seems to want all the traditional mood music and shadows of a conspiracy thriller without the conspiracy. We know who Deep Throat was and are repeatedly assured he was a good guy. It doesn’t quite wash: the complexity of Felt’s motives are left untouched in the interests of having a fiercely principled hero at the film’s centre.