Lewis Hamilton has a four-point lead heading into the final race of the Formula One season, but the title race is still effectively wide open.

The Englishman's lead gives him some breathing space, and ensures that he can play the percentages as he seeks to secure the title.
But Hamilton has already said he would prefer to win the race and take the title in style - and, analysing the mathematics of the title chase, it is easy to see why.

Hamilton leads on 107 points, from his McLaren team-mate Fernando Alonso on 103 and Ferrari's Kimi Raikkonen on 100. The points system goes 10-8-6-5-4-3-2-1 from first down to eighth place.
But if drivers finish the season level on points, then a count-back system is employed, starting with comparing how many wins they have, then looking at second places and so on.

And, depending on the results, the title could even be decided on who has the most fifth places. It is that close.

Hamilton will be champion if:
- He wins or finishes second
- He finishes ahead of both his rivals
- He finishes no lower than second if Alonso wins
- He finishes no lower than fifth if Alonso is second
- He finishes no lower than fifth if Raikkonen wins
- He finishes no lower than seventh if Alonso is third and/or Raikkonen is second
- He finishes no lower than eighth if Alonso is fourth
- If Alonso if fifth or lower and Raikkonen finishes third or lower.

For Alonso to win, the Spaniard must:
- Win with Hamilton third or lower
- Finish second with Hamilton sixth or lower
- Finish third with Hamilton eighth or lower, and Raikkonen failing to win
- Finish fourth with Hamilton lower than eighth, and Raikkonen lower than second