Despite the attachment of two heavyweight names like Oliver Hirschbiegel and Naomi Watts to Diana, this biopic of the late Princess of Wales is an exercise in frivolity. Hirschbiegel was behind the excellent, Oscar-nominated Downfall, which depicted the final days of Hitler's reign, but here he has delivered an overly-reverential, silly and shallow account of Diana's life.

From the time it was first announced, the movie was feverishly anticipated in the press. Now that it has been completed, Diana has been almost unanimously panned by critics. And for good reason.

This was always going to be a sensitive subject, as the People's Princess still holds a place in the heart of so many since her untimely death in Paris in 1997. Diana opens in the aftermath of the car crash that ended her life and that of Dodi Fayed, and then rewinds two years to uncover the events that led up to this point.

The focus is the relationship between Diana and Pakistani heart surgeon Hasnat Khan (Naveen Andrews), picking up as Diana's marriage to Prince Charles, who is never seen in the film, is ending. Diana falls head over heels for the jazz-loving, chain smoking Hasnat, but their journey to happiness is not smooth, due to the intensifying press intrusion in her life, which he cannot accept; and the traditional values of his family, who cannot accept a divorcee.

Their romance plays out like a tacky soap opera, depicting Diana as a desperate, slightly hysterical woman who will go to any lengths to keep her man, including sneaking into his house and doing the dishes when they're going through a tough patch.

Woeful dialogue is the film's worst offender, and the script from Stephen Jeffreys is littered with utterly unbelievable lines. When Watts and Andrews have to utter sentences like: "Yes, I've been a mad bitch" and "You don’t perform the operation, the operation performs you", you can't help but cringe - and applaud them for somehow keeping a straight face.

The whole tone of Diana is horribly misjudged and goes to show that it was just too soon to delve into her life, especially a treatment that is so wholly superficial.

Watts delivers a carefully considered performance as the Princess, obsessively researching Diana's gestures and facial mannerisms to try and accurately capture her character. It's a fairly impressive transformation, but the weak script ultimately scuppers any chance Watts had to bring any level of insight or gravitas to the role.

Ultimately, Diana doesn't even begin to scratch deeper than the surface of Diana's complex character, and despite a huge budget and the big names attached, comes across as a cheap, made-for- TV movie.

Sarah McIntyre