After a couple of races that made the Championship look like it would be decided between Michael Schumacher and Kimi Raikkonen, the script of the season has changed radically since Monaco, and now both the Williams drivers are back in the hunt following their one-two finish at the European Grand Prix. Richard Barnes analyses the weekend's events and their effect in the battle for the title

After the Austrian Grand Prix in mid-May, it seemed like the season's script had been well established. Despite a shaky start in the hybrid F2002, Ferrari had come on strong with the F2003-GA, and three successive victories had eased Michael Schumacher into a confident second place in the Championship. Although still trailing McLaren's Kimi Raikkonen narrowly at that stage, the German looked to have both the machinery and the consistency to inevitably haul in his young rival, who was still waiting for the debut of the 2003 McLaren. Williams, meanwhile, seemed destined to play Championship bridesmaid again, nursing the disappointing FW25 to a series of missed opportunities and minor points finishes.

Three races and two Williams victories later, the script has been rewritten totally. In a fascinating and unpredictable season, the mid-term swing in fortunes has served to highlight the diverse development curves of the three main Constructors' Championship protagonists. Ferrari's legendary ability to develop the car over a full season seems to have hit a brick wall, Williams' early season 'lemon' has turned into a winner and, against the predictions, McLaren's reworked year-old design has managed to keep pace with their 2003 rivals. There hasn't been a season in memory during which three cars, at such greatly differing points in their evolution, have been balanced so finely in terms of outright performance.

Qualifying for Sunday's European Grand Prix pitted all three frontrunners within a tenth of a second of each other. Even with the slight variation in fuel loads, it was a remarkable reflection of just how narrow the margins have become. It also illustrated how car development can radically alter a driver's performance.

Whatever aerodynamic magic Williams have concocted since Austria, it's benefited Ralf Schumacher more than his Colombian teammate Juan Pablo Montoya. Although Schumacher has been a model of consistency in finishing every race in the points so far, it took him eight races to record his first podium finish of the season. Montoya, while more erratic over the course of the season, has looked far more competitive and able to drive around the problems of the early-season FW25. Yet, since Monaco, Schumacher has revelled in the aerodynamic improvements incorporated by the designers. While Montoya is still more likely to wring something extra out of the car, Schumacher looks to be the more threatening and consistent, especially if the handling balance stays as is.

The difference is even more marked at McLaren. It's not often that David Coulthard gets a car balanced to his liking, but when he does he can beat anyone in the field. Sadly for the Scot, the MP4-17D is not one of those cars. If Kimi Raikkonen is looking forward to the McLaren MP4-18 to sustain his Championship challenge, Coulthard must be hoping that the new car will save what is left of his reputation. For, even during the height of Mika Hakkinen's Championship glory in 1998/9, Coulthard was usually closer to his Finnish teammate than he is now. After yet another disappointing qualifying and race performance on Sunday, the Scot has drawn gentle but pointed criticism from McLaren managing director Martin Whitmarsh.

While Coulthard couldn't be blamed for Fernando Alonso's wildly erratic braking in front of him, the Scot shouldn't have been trailing the Renault in the first place - especially not when Raikkonen was leading the field convincingly from a well-deserved maiden pole position. There is no question that the McLaren's balance is currently more suited to Raikkonen's style but, after nine full seasons in F1, Coulthard should have developed the ability to drive around the car's shortcomings. If Coulthard is going to pitch himself as a worthy rival to Michael Schumacher, that is one of the key benchmarks on which his claim will be judged. Although Schumacher also had little reason to celebrate his performance on Sunday.

Since his return from the injury sustained at Silverstone 1999, Schumacher's motto has been 'Maximise every opportunity'. Yielding to the visibly faster Montoya would have earned the German a sixth successive podium and six more WDC points. Instead, that one moment of petulance cost him two Championship points, and it could so easily have been four if he hadn't managed to stop with his front wheels still on the racing surface. With Championship rival Raikkonen out of the race already, some would argue that he had nothing to lose - his three point Championship lead would have stayed intact, even if he had not received assistance from the marshals. Alain Prost disproved that line of reasoning years ago, and it's even more applicable today.

The new points system has placed a premium on consistency. Even under the more forgiving points system of 2002, Ferrari were willing to risk their image with the fans for a mere four WDC points - and that when Schumacher was already leading the Championship by more than 20 points. Ferrari technical director Ross Brawn's angry criticism of Montoya belies the true frustration, that his star driver made an unforced error when he could ill afford to. Montoya's move was daring but clean, and the Colombian proved once again that he's the only driver in the field who can rattle Schumacher consistently. There are times when it might reward Schumacher to react in kind to Montoya's aggressive passing moves. Sunday was not one of those times. Beaten for pace, Schumacher would have been passed sooner rather than later. Yielding and taking the six points would not have earned Schumacher lavish praise for guts and glory, but it was the intelligent thing to do. And, most of the time, Michael Schumacher is the most intelligent driver in the field.

The unexpectedly poor result leaves Ferrari in a predicament, and the Championship in an intriguing standoff. With predictions of Michelin superiority again at Magny-Cours this weekend, and testing banned during the summer recess in August, Ferrari and Bridgestone have little time to find answers to the growing Michelin superiority. It's a recurring theme for Maranello, being tied to the waning power in tyre production while their rivals benefit from fresh ideas and faster rubber. In 1998, Ferrari managed to coax some extra performance out of Goodyear. Ultimately, it was to no avail, as Bridgestone-shod McLaren went on to claim both Championships. If the situation doesn't repeat this year, it surely will in 2004.

McLaren also face troubling questions, whether to launch the marginally reliable 2003 car earlier than they would have liked, or risk more DNF performances at the time when Raikkonen needs every point available. McLaren should go with the new car as soon as possible. If nothing else, David Coulthard may find it more to his liking, and help the Woking team towards the title they really want - the Constructors' Championship. Raikkonen cannot carry the constructors' effort on his own.

Incredibly after such a poor start to the year, Williams could now be in the prime position for both Championships. After nine successive points finishes, and only trailing brother Michael by fifteen points with a potential seventy points still on offer, Ralf Schumacher has re-emerged as a legitimate Championship threat. Another Ralf win, coupled with a single Michael DNF, will see the WDC battle almost back to all-square. In the Constructors' Championship, they're looking even stronger. Even if Juan Pablo Montoya fails to overhaul Ralf and challenge for the WDC, he looks likely to accumulate more CC points than either Coulthard or Ferrari's Rubens Barrichello.

In each close season, there is a key moment that reflects a lost opportunity and a new Championship picture emerging. In 1998, it was Schumacher's devastating shunt with David Coulthard at a soaked Spa-Francorchamps. 1999 had several such moments - Schumacher slamming into the tyre wall at Silverstone and Mika Hakkinen in tears after his driver error at Monza to name just a couple. A year later, it was Hakkinen's stunning pass on Schumacher at Spa that remoulded the Championship picture. And in 2001, Hakkinen's last lap failure at Spain epitomised a season of lost opportunities. When all is said and done this season, 2003's most symbolic moment may be the plume of smoke from Kimi Raikkonen's blown engine on Sunday, or the sight of Schumacher stranded in the gravel and frantically motioning the marshals over to assist him. Although, with seven episodes still to run in this engrossing series, the plot could still have many more wrinkles.