The McLaren-Mercedes team will persevere with its ageing MP4-17D for at least the next two grands prix - at the Nurburgring and Magny-Cours - after delaying the introduction of its latest model for a further month.

Despite initially suggesting that the car - which the team hopes will continue to take the fight to Ferrari and propel Kimi Raikkonen or David Coulthard to a first world title - would make its race debut at this weekend's European Grand Prix, the team has revealed that it is still not entirely confident of the MP4-18's reliability, and will continue to use the older model in the hope of being able to score regular points finishes to keep both drivers in the championship hunt.

"It is imperative that we do not jeopardise our championship campaign by introducing a car which has not been developed sufficiently to achieve the requisite level of reliability," a spokeswoman told Reuters today [Monday], "The logistical challenges of the two back-to-back' races at the Nurburgring and Magny-Cours do not support an introduction of the new car during these races. We will therefore only introduce the new car once we are confident that it will enhance our championship programme.

"Our goal is still to win the 2003 world championship, and we believe that we are in a good position to do so and that the strategy to employ the much developed MP4-17D in the first half of the season has provided us with the platform from which we can achieve our goal."

The new car has made two test outings in the past month, running with Alex Wurz as well as the two regular drivers either side of the Canadian Grand Prix. However, it has yet to show full reliability and has also suffered two crashes that have set back the development process. The team has also suggested that it may follow Ferrari's lead in fielding just one of the new cars on its debut - as the Scuderia did in Brazil a year ago - and leaving Raikkonen to run one of the older car's until the MP4-18's potential is established.

McLaren currently lies second in the constructors' standings, nine points adrift of Ferrari, while Raikkonen only surrendered the lead of the drivers' standings after Michael Schumacher won in Canada a little over a week ago. The Finn is now three points behind his German rival.