After big wins at the Screen Actors Guild awards - and earlier this month at the Golden Globes - Three Billboards Outside Ebbing, Missouri appears to be front runner for best picture when this year's Oscar nominations are announced on Tuesday.

But in reality, this year's race for best film is still one of the most open for years.

Three Billboards may have picked up some of the big prizes, but Academy voters are still more than capable of moving in a different direction - especially as the Oscars doesn't use a first past the post system for picking the winner.

Three Billboard's Sam Rockwell and Frances McDormand.

Instead, it employs a preferential ballot, where voters' second and third choices can be vital in deciding which film will win.

It's a system that favours consensus over passion, and a film like Three Billboards - which has proved controversial to some - is the film most likely to be a loser under the current voting rules.

So it would be foolish to write off the chances of mysterious love story The Shape of Water, coming of age tale Lady Bird, or even horror film Get Out.

Studying the winners of other awards bodies is also becoming less valuable when it comes to the Oscars.

Following the #OscarsSoWhite campaign, the Academy has attempted to make its membership less old, white and male. And around 1,500 members of the current voting membership - that's 20 per cent - have only joined in the last two years.

Some things do seem clear: Frances McDormand's performance as a bereaved mother in Three Billboards is the one to beat for best actress. Similarly, Gary Oldman's Winston Churchill in Darkest Hour is way out in front for best actor.

While over the past couple of months Alison Janney, who plays Tonya Harding's mother in I, Tonya, and Sam Rockwell who portrays a bigoted cop in Three Billboards, have edged ahead of Laurie Metcalf (Lady Bird) and Willem Dafoe (The Florida Project) in the best supporting categories.

Source: BBC