If the truth can’t be told using freedom of speech then real journalism is dead. This is one sobering message from screenwriter James Vanderbilt’s directorial debut Truth based on sacked CBS producer-reporter Mary Mapes’s book Truth and Duty. The sad fact is there is always some sort of political persuasion in all reporting and programming – someone has to pay the bills. However, it’s always hugely energising to watch a drama trying to challenge the powers at play. The difference here is this actually happened in real life.

Looking for their next big scoop for TV news programme 60 Minutes II, Mapes (Cate Blanchett) and her research team (a commendable Dennis Quaid, Topher Grace and Elizabeth Moss) come into possession of some photocopied military memos that suggest George W Bush may have dodged drafting for Vietnam by going AWOL from the Home Guard while training to be a pilot.

The subsequent CBS programme hosted by veteran broadcaster Dan Rather (Robert Redford) causes a stir during Bush’s presidential re-election campaign in 2004, sparking a witch-hunt against the newsmakers as the authenticity of the memos is called into question. Lauded Mapes and Rather come under fire for simply trying to report the truth.

This film has such a firebrand performance from Blanchett as quick-thinking Mapes that she effortlessly rallies our support from the get-go. Her enthusiasm for the material is evident as she channels this into an engaging performance. This consists of lots of scenes of her and the usual smart people uncovering the pieces to the puzzle, simultaneously helping gather momentum – like any good police drama that involves stacks of paperwork and a handy whiteboard. Vanderbilt’s screenwriting know-how is well served here, even though he actually has Blanchett’s screen charisma to thank for pulling it off the page.

Redford is also highly convincing and rather humbling as news anchor Rather, once again showing that with age comes wisdom and being content in one’s skin – and that of another prominent person you’re emulating. Along with Blanchett, the pair nicely shares command of the screen when both are in the frame, giving gravitas to Mapes and Rather’s strong bond. This does tend to mask some directing inconsistencies, where elements could be tighter. However, Vanderbilt’s criticism of CBS’s management ethics cannot be ignored – something the American broadcaster has recently acknowledged in banning the film’s ads.

Truth cannot resist plugging the ‘truth will set you free’ in virtually every scene too, though it all hangs well like any aptly made political drama, employing the same production values and corporate blue-grey hues, cinematography-wise. Still, Truth is a very rousing piece, bolster by its true story, as all corruption should be challenged in a perfect world. It’s also very timely and effective, again, striking a chord in austerity-hit times. If nothing else, this ought to be seen for another awards-worthy, killer Cate Blanchett performance.