Downton Abbey was in many ways an accidental phenomenon.

Initially, a well-constructed British period drama designed as entertaining Sunday night froth, it became a global hit and so now hits the big screen.

In its later seasons, Downton the series became a bit of a soap opera rather than a serious drama - EastEnders for people whose idea of knife crime is using the wrong cutlery for your starter.

Happily, our return to the stately home and the aristocratic Crawley family showcases what was best about the show - its likeable characters and sharp wit - and uses cinematic grandeur to create an impressive and enjoyable drama rather than a tepid cash-in.

Part of the film's success is it centring on a major set-piece occasion, preventing the plot from wandering into the indulgences of its creator Julian (now Lord) Fellowes. King George V is visiting Downton, and everyone, from the Earl and Countess of Grantham (Hugh Bonneville and Elizabeth McGovern) to the lowliest staff member has feelings of excitement and trepidation.

The visit of royalty is a chance for all to shine - but places stresses and strains on the family due to the unconventional past that was explored throughout the TV show's six seasons.

The Earl's daughter, Lady Mary Crawley (Michelle Dockery), is having doubts about the future of the family and their home. Her late sister's widower Tom Branson (Allen Leech) is under suspicion due to his Irish republican leanings.
Meanwhile, family matriarch the Dowager Countess of Grantham (the indomitable Maggie Smith), is plotting to harangue her cousin Lady Maud Bagshaw (Imelda Staunton), the Queen's lady-in-waiting, about her plans to cut the Crawley's out of her inheritance.

As for the staff, they quickly learn that a royal visit is not quite all it's cracked up to be - as the King's tyrannical butler (David Haig) makes it clear that their services will not be required on the day of the royal visit itself, as the King travels with his own retinue including everything from a chef to a dressmaker.

Turmoil among the staff prompts the Earl to send for the now-retired butler Mr. Carson (Jim Carter), who returns to help run things and stave off any insurrection, much to the chagrin of his younger replacement Thomas (Robert James-Collier).

Among the all-star cast, Leech - whose Branson is world-weary and wise beyond his years, but still with the looks of a matinee idol - gives a stand-out performance.

Inevitably though, the best scenes are between Smith and Staunton - warring battleaxes with a softer side beneath their sharp wit.

Although Downton will no doubt find its way on to many people's small screens this Christmas, director Michael Engler has managed the transition from TV to cinema well, utilising sweeping shots of Highclere Castle (the real stately home that doubles as Downton) and the surrounding countryside, as well as lavish interior shots that display the glamour of wealth in the 1920s jazz age.

Yet, Downton is Fellowes's baby - as the show always lived or died on the quality of his scripts. At his best, Fellowes is an astute observer and satirist of his own class, but at his worst, he can also be a solipsistic celebrator of its excesses.

Downton the movie showcases both his strengths and failings as a writer - as it is full of amusing one-liners and strong character moments but pulls back from turning these into something more meaningful - and occasionally becomes just too much.

There is, after all, only so many times you can hear how tough life is for people who are waited on hand and foot, and whose ornaments cost more than their servants would earn in a decade.

As a result, the film is unlikely to win over those for whom spending a slightly overlong two hours in the company of complaining toffs is like visiting the seventh circle of hell. However, it is likely to delight fans of the TV show, who will get a sugar rush that, unlike the sprawling messy plots that characterised the final seasons of the show, is happily condensed into a tightly woven story.