Stars can be important elements when it comes to packaging elaborate European co-productions. Obviously, casting a German lead may help sell the film in German-speaking territories or raise funding in those territories. The Weinstein Company's Colin Vaines acknowledges that with lower-budget European films, directors are often what sell the work internationally. 'But if you're going out seeking funding with a patchwork of money from different countries, it can be enormously helpful to have maybe a Spanish star or to add a French actor or Italian actor into the mix.'

The higher the budget, the more intense the pressure to cast names. French director Francois Ozon suggests that he was extraordinarily lucky to be able to make the $15m English-language film Angel - which is closing the Berlinale - with a relative unknown (Romola Garai) in the lead role. 'It is very risky casting. Financiers always want big names,' Ozon suggests.

The irony is that the economics of European movies rarely justify the use of expensive, big-name stars. Paul Verhoeven's recent Black Book is a case in point. At $20m, it was the most expensive film ever made in the Netherlands. If the cast had included stars, the budget would have risen yet further and it would have been well-nigh impossible to finance the film in Europe or to shoot it in Dutch and German.

Few European films are financed on the basis of stars alone. They are one element, but not always the most important one. 'The game in America is to lend the (star) name to a production and then find the funding,' suggests PR consultant Lucius Barre. 'That engine doesn't function in Europe. It's the film-maker and the story. With very few exceptions, European actors are added value and not the core assets of a new project.'

Stars will often have to work for a fraction of their Hollywood fees to appear in European movies. Nor does their star status necessarily translate into box-office receipts. Ewan McGregor was widely seen by critics to have given one of his finest performances in David Mackenzie's Young Adam, but that did not change the fact that it was a low-budget arthouse film.

UK sales agent Joy Wong from The Works suggests that having a major star like McGregor aboard a first-time feature like Scenes Of A Sexual Nature helped flag up the project to buyers. Nonetheless, she has also handled films that have been bursting with well-known star talent, for example Richard E Grant's Wah Wah and Stephen Fry's Bright Young Things, which have remained a tough sell internationally.

Some argue that stars can even be damaging for European films. In the UK, for example, when projects are packaged around stars, budgets escalate and projects can no longer make economic sense.

'Many, many times, I say cut the budget and make the film the star,' notes casting director John Hubbard. 'I wake up screaming these lines. When people come in and say the budget is $12m or $15m, or even $8m or $10m, I say clearly your investors will want names. They'll want somebody they've heard of. It's so hard at that level. We mustn't forget that Hollywood - and this is a massive generalisation - is 100% about money. It's run by agents and managers who are on commission. It's a basic business principle that the more money they can make out of their clients, the more money they can make for their companies. That's what makes it so hard.'

A key problem, Hubbard believes, is that European producers do not allow enough money for talent. 'Often you hear producers saying they can't go beyond $250,000. All this is governed by sales estimates. Producers say that if they pay more, the film will cost them more than they are going to get for it when they sell it on the market. This is a fundamental problem.' In other words, the producers want to have it both ways - to access the stars without paying them their full fee. When the sums do not add up, either the idea of casting the star is dropped or the project is abandoned.

'It cuts both ways,' says The Weinstein Company's Vaines. 'Everybody is chasing after a relatively narrow pool of talent that has the possibility of attracting money. Clearly, the higher the profile of a young actor like James McAvoy, the more his attachment becomes an incentive. You make the allowance that the above-the-line is going to rise slightly, but in general in European terms, most of the talent is realistic about what the budget can and can't bear.'

The Weinstein Company, like the old Miramax, tries to cast on the basis of talent, not nationality. 'That's Harvey's boundary-blindness you could call it and his enthusiasm for European talent in general,' notes Vaines.

'It's hard when you're trying to make different types of films to apply blanket philosophies,' says Allon Reich, head of production at DNA. On certain DNA films, for example Danny Boyle's 28 Days Later or Juan Carlos Fresnadillo's 28 Weeks Later (due out in the early summer), the movies are marketed on the back of the genre and director. By contrast, on something like Notes On A Scandal, casting is paramount. 'With all these genre films, very few have big stars in them. But Notes On A Scandal, if you go one notch down on the casting, you're really in trouble. You feel, 'Why aren't we watching it on TV'''