Williams' race drivers seem resigned to a full season at the back of the grid.

The once-great British team's slump is so severe that co-founder Sir Patrick Head has been brought out of retirement.

"It's the right step," Robert Kubica is quoted by Auto Motor und Sport.

"But Patrick Head can do nothing alone. He needs the whole team."

The problem, the Polish driver said, is that Williams actually risks falling even further behind during the course of this year.

"In the time we are working on one problem, we are losing ground elsewhere," said Kubica.

He has struggled in the 2019 car alongside rookie George Russell so far this year, explaining: "I just cannot attack. I'm always on the verge of going off."

Things looked better in China, but Kubica explained: "Our car has not gotten better. It's just that there are more corners in Bahrain for us to lose time."

Barcelona, for instance, will be a serious problem.

"For us, corners 3 and 9 are still real corners. The others go through there flat."

One big problem for Williams is that it is not producing enough spare parts. The other major problem is that the parts that are produced are not high quality and consistent.

"We have to take one step after the other," said Kubica.

But Kubica said he is at least feeling fully capable of doing full race distances, even if some questioned his fitness with his permanent injury.

"There were doubts and I too sometimes asked myself the question. But today I know that I do not need to worry about my fitness," he said.

Russell, on the other hand, recently got a taste of Mercedes' 2019 car, but he promised to keep the top team's secrets close to his chest.

"I can at least tell them what direction to go. I can tell them what the Mercedes does on a particular corner compared to us," he said.

And the reigning Formula 2 champion says Williams has a lot of work to do.

"If we want to catch up, we would have to develop three times as fast as the others," said Russell. "Because they are also making their cars faster.

"We have to remain positive, but also realistic. It would be presumptuous to expect more than where we are today."