By Andrew Benson
McLaren look set to have to rely on their 2002 car for at least another two Grands Prix after deciding not to give their new car its debut this week.
McLaren have turned the tables on Ferrari so far this season
The team had said they would test the definitive 2003 car, the MP4-18A, for the first time this week, but it is not ready, and McLaren would not confirm when it would take to the track for the first time.
A spokeswoman said there would be "a low-key launch of the car within the next month and the first test will follow shortly after that".
The new car is now likely to race for the first time at the Austrian Grand Prix on 18 May - but McLaren have said they will not race it until it is as reliable as the car they are using at the moment, the MP4-17D.
That is a revised version of their 2002 car, which has won all three of this year's Grands Prix - with Kimi Raikkonen provisionally winning two races and David Coulthard the other.
The two are first and second in the world championship and Raikkonen now has an 11-point lead over Coulthard - and an 18-point advantage over reigning champion Michael Schumacher.
Ferrari, who have also started the season with a revised version of their 2002 car, are to introduce their new car for the next race, the San Marino Grand Prix at Imola on 20 April.
The world champions have had a disastrous start to the season, with only one podium finish - by Rubens Barrichello - in three races.
Nevertheless, most F1 insiders believe the Ferrari has been the fastest car in the first three races - which means they are likely to have even more of a pace advantage at Imola.
McLaren's excellent start to the season has been aided by the mistakes made by Ferrari - and especially Schumacher, who has committed errors in all three races.
However, the team have dramatically closed the gap to Ferrari over the winter and will be confident of racking up more points with the MP4-17D before the new car is introduced.