A couple of nights ago a friend of mine went to see Invictus at the cinema and has been raving about it ever since; I've been told in no uncertain terms that I must go and see it, partly for the drama and partly because 'it shows Mandela as a hero'. I haven't got round to it yet but as a sports fan it certainly carries some appeal.

The film, for those of you who haven't heard of it, tells the story of the 1995 Rugby World Cup held in South Africa and especially of the political upheaval the country had been experiencing in the post-apartheid era. More specifically it focuses on the efforts of Nelson Mandela - the newly elected president and hero of the transition to full representative democracy - to unify the fractured population in support of the Springboks, South Africa's national team but seen by many blacks as an institution of the hated white supremacist minority. It's probably not going to spoil the film too much by already knowing the outcome of that tournament.

Historical events have always provided a fertile inspiration for film makers, and it's not entirely surprising; great world events naturally lend themselves to on-screen story telling. And ever since then the ability for celluloid to distort the truth - for dramatic purposes or otherwise - has proved as controversial as the films themselves have been popular.

One of the earliest - and most notorious - examples is the 1945 film Objective, Burma! which depicted a purely American force fighting in what had in reality been a largely British Empire theatre of war. So recent was the memory of the war in the UK and so great was the public outrage at the blatant manipulation of the truth - lead actor Errol Flynn safely sat out the war in California - that the film was barred from British cinemas until 1952.

And ever since then war and conflict has provided the source for possibly more notoriously historically inaccurate films then any other genre. The Patriot, Braveheart, Pearl Harbour, U-571 - all of them drawing their influence from war and all of them - just like Objective, Burma! - guilty of altering the truth for dramatic effect.

Which raises a very pertinent moral dilemma: should films which purport to be depictions of actual events be allowed to claim as such if the events it shows are significantly different from their factual counterparts?

Take Braveheart, for example; this Oscar-winning film was credited with assisting in the revival of Scottish nationalism which culminated in the re-opening of a national parliament in Edinburgh several years later. But it also came under fire for its unerring lack of historical accuracy - a fabricated romance, belted plaids before any such thing existed, a battle primarily famed for its bridge that featured anything but onscreen - and distinctly anti-English undertones. Director Mel Gibson defended his liberal treatment of fact by arguing that the changes were much more "cinematically compelling" than a simple recounting of recorded history.

And perhaps that's not surprising; film as a medium is primarily designed to entertain, and history told through the mere constraints of objectivity and accuracy might make for a dull audience experience and a subsequently low return at the box office.

But others suggest that film - powerful as it is - should have have a duty to portray history without more then ephemeral alteration lest audiences gain the impression that what they see is fact. For many Braveheart appeared to be little more then an exercise in nationalist propaganda, and the thesis that the film played an influential part in the development of nationalist consciousness north of the border merits close examination. Similarly other films may find that their dramatic historical interpretations may begin to replace actual accounts in the minds of those who access mediums other than television and film on a less regular basis.

Those that defend the actions of such films argue that artistic licence merits the on-screen alteration of the truth. But to perceive films as constituting nothing but a form of entertainment is to be woefully naïve, for they also have the power to influence, to educate and to inspire. And, just like my Invictus-loving friend has proven, films have the power to stay in the mind for days and weeks after the event. Mere entertainment doesn't come close to describing it.