There's something undeniably familiar about the opening titles montage of The Kennedys. The slow motion billowing stars and stripes and sombre theme music appear to have been lifted directly from the long-running and much-loved drama The West Wing.

But this is no political fiction, rather a purportedly fact-based mini-series chronicling the rise to power of President John F Kennedy, his all too brief 1,000-day tenure in the White House, and the aftermath of his assassination. Yet, where Aaron Sorkin's awards-laden ratings-winner quickly cemented its reputation as a small screen classic, The Kennedys may go down in TV folklore as an ill-conceived, misfiring folly.

Even before filming began last summer, the eight-hour saga of Camelot and America's most famous family was in trouble. Kennedy historians, having been granted an early look at the scripts, were falling over each other to highlight historical inaccuracies, the unpalatable bending of truths and what former JFK speech writer Ted Sorenson described as "character assassination".

Once the production wrapped in January, it received an astonishing blow when the powerful A&E Television Network announced it would not be premiering the show on its prestigious History channel, as originally planned. The official statement read: "After viewing the finished product in its totality, we have concluded this dramatic interpretation is not a fit for the History brand." When a handful of other stations also passed on the project, the series finally found a home on the relatively tiny ReelzChannel network with only a fraction of the broadcast 'reach' hoped for.

Quite why a series deemed to run fast and loose with the truth in America should then be described as a "major coup" by the head of AETN's UK operation and given a bold and blustering promotional push on Blighty's own more modest History channel in April is odd to say the least. Did the network think British viewers were less concerned with authenticity, or might it have been a desperate and cynical move to reduce the red on the balance sheet of a costly endeavour all but disowned in its homeland?

In truth, the estimated $30 million price tag is not outrageously expensive for such an ambitious production top-lined by actors with healthy and respected cinema resumes, but neither is it especially cheap. Certainly, Oscar nominees Greg Kinnear as JFK and Tom Wilkinson as his father Joe would expect to be paid top dollar, as would producer Joel Surnow, after the runaway success of his small screen creation 24.

So, with all that talent in front of and behind the camera, where did The Kennedys go wrong? Arguably, there may have been too great a temptation to merge undisputed facts with allusions to many of the unsubstantiated rumours that continue to orbit around a man who, nearly 48 years after his death, remains the subject of more biographies than any other individual in history. Did patriarch Joseph Kennedy really broker a deal with Chicago mobster Sam Giancana to secure his son's 1960 election triumph? Let's hint that he did, but combine it with other touted behind-the-scenes machinations involving Frank Sinatra. Did Jackie Kennedy really threaten to leave her husband at the height of the Cuban missile crisis? Who knows for sure, but it might give the narrative a bit more dramatic oomph.

Therein lies at least part of the problem: for its first major dramatised programme, the US History channel was clearly expecting a well-researched and faithful account of a pivotal time in American - and world - politics, but was instead presented with scattergun mosaic of hearsay and half-truths with all the gravitas of a mid-market soap like Falcon Crest.

Kinnear is a fine actor, bringing great nuance to comic or light dramatic roles, but he's plainly out of his depth as the leader of the free world, lacking the screen charisma necessary for such an iconic figure. Wilkinson fares better as Kennedy senior, although the exposition-packed script all but spoon-feeds the viewer a guide to what's going on, forever undermining a part that should be played with more subtlety - manipulative puppet-masters rarely explain their every move on camera.

As the emotionally-fraught and priority-torn Jackie Kennedy, a simpering Katie Holmes is just laughable. It doesn't help that she never looks older than 14, and the episodes in which her energy levels are boosted after visits from her husband's own 'Dr Feelgood' physician mirror the sort of over-simplified druggy journeys exemplified by Phil Mitchell's rollercoaster two-month flirtation with crack in EastEnders.

Somewhere in the middle of this woeful whirlwind of hamming it up is the series' one genuinely praiseworthy performance. A reserved and understated Barry Pepper hits the mark in every scene as Bobby Kennedy, initially reluctant to accept the position of Attorney General in big brother's cabinet after the election, but once there remaining true to the policies and promises of the manifesto, challenging not just racketeers and FBI director J Edgar Hoover, but also powerful figures in the White House itself, like Secretary of Defense Robert McNamara.

The portrayal of Bobby Kennedy has survived relatively unscathed, attracting less criticism from political commentators all too eager to pull at the threads of the rest of the production's attempts at historical veracity.

However, Surnow and his writer Stephen Kronish can't seem to help themselves when it comes to the President, who tends to stumble into caricature as a womanising ne'er-do-well. As you might expect, JFK's oft-debated relationship with Marilyn Monroe gets an airing, although as played by Charlotte Sullivan, the most celebrated Hollywood sex symbol of the age comes across as a ten-a-penny large-breasted blonde stalker.

Martin Sheen looms large over this disappointing and presumably soon-to-forgotten affair for two reasons. His version of the real-life president in the 1983 mini-series Kennedy has yet to be bettered, and it's only a few short years since the irrefutably JFK-like Jed Bartlett gave viewers a fictionalised ideal of a commander-in-chief just about everyone would vote for. His was a White House that rang with truth, where real world concerns were skilfully woven into a well-structured and brilliantly-acted drama.

Yes, the producers of The Kennedys have unashamedly lifted the stirring titles of The West Wing; if only they'd had the daring to steal a little more.

The Kennedys begins on BBC2 on 17 June at 9pm.