With a title from the US constitution (life, liberty and the...), you'd expect a very American film and this is indeed a rags-to-riches tale. The unusual aspect is that it gives you the rags and leaves the riches for later - if you get up before the endtitle, you wouldn't even know about them. You may well feel, as I did, that you'd rather avoid a film about a bone-density scanner salesman who aspires to be a stockbroker, but it does have the considerable plus of Will Smith in an adapted life story.

Smith hasn't been in anything memorable since Ali six years ago, but he's very good at raising what might have been pure schmaltz into something watchable, as with the romcom Hitch last time out. There's one more bonus to what is mainly a father-and-son tale: Smith performs with his own offspring, now aged eight and on this evidence - no doubt with skilled assistance from Italian director Gabriele Muccino - a natural. With a few exceptions (Ryan and Tatum O'Neal spring to mind), this is apt to be a disastrous star indulgence but there's no faking the natural relationship on show here.

What this means for the Smith family is anyone's guess but I like to think that it may be a multimillionaire dad's way of giving junior some insight into how the other half live. The other half in this case being a salesman slogging around without a car with bulky medical products doctors tend not to want (the scanner is a glorified X-ray machine) while being abandoned by his wife and thrown out of his flat for due rent. And losing his car. And slogging around San Francisco, where streets are more vertical than horizontal. And performing an unpaid intern job cold-calling with a one-in-20 chance of turning into a paid job. And selling blood. Film buffs will recognise a plot close to Italian 1948 classic Bicycle Thieves. This has a different agenda but as family films go, it's not bad, and it might make your offspring think his or her lot in life isn't so bad after all.