By Andrew Benson
The Williams team say their car will not be fast enough to win races at the start of the Formula One season.
Williams have been having problem with their new car's aerodynamics
They have run into problems with the new FW27 in pre-season testing ahead of the Australian Grand Prix on 6 March.
Owner Frank Williams said their chances of winning in 2005 would be "slim to begin with, but we'll get better".
He said McLaren and Renault were heading into the new season as the strongest teams, followed by world champions Ferrari.
"We've certainly not got a quick enough car, but I'm confident it will be reasonably competitive in Australia and will get better from there," said Williams.
Williams director of engineering Patrick Head added: "Renault and McLaren look very strong. I'm impressed with them particularly.
"Ferrari don't look too bad, but the interesting thing is going to be Ferrari's new car rather than their intermediate one."
Ferrari are starting the new season with a modified version of last year's car but are building an all-new model that they say they are planning to use from the fifth race of the season.
"Williams are behind where we thought we would be," Head said.
"The car has been pretty reliable but aerodynamically we are a bit behind where we thought we were."
He said the team had had some problems with the operation of their high-tech new wind tunnel, the device in which the all-important aerodynamics of an F1 car are designed.
But he added: "We're learning a lot and we are pretty confident we won't spend a year before we start winning races.
"We will be significant players very much earlier in the season than we managed last year and in 2003, when it took us eight races to get competitive.
"I think it will take us less time this year, but of course we wanted to be competitive from the first race and I don't think we will be."
Both men said they were happy with how their new driver line-up of Australian Mark Webber and German Nick Heidfeld was performing.
Head said: "People might say Webber and Heidfeld is not a very strong line-up compared to, say, Kimi Raikkonen and Juan Pablo Montoya at McLaren.
"I'm not going to say they are better, but haven't seen anything that indicates our laps times are slower (because of the drivers).
"We don't go into the season thinking we can't be successful because we haven't got the drivers."
Williams added that he expected it to be a "very good season", with a lot of competitive cars.