Robert Kubica's relationship with Williams appears to be breaking down completely.

The Pole, who has already announced his departure at the end of the season, slammed the struggling British team after the Japanese GP.

Kubica says that after testing a new wing on Friday, he was not told that the component would be taken off his car for qualifying and the race.

"For the first time in a long time, the situation improved significantly with the new wing," he told Poland's Onet Sport at Suzuka.

"But it was removed before qualifying, and not for matters related to the track, but for other reasons. I got into the car on Sunday and it was different than before.

"The team didn't inform me and this is not the right thing to do.

"If you have a driver in a team saying he can squeeze more out of it now and there are no major problems, I think every team would like that.

"For some strange reasons with Williams it was not like that.

"I knew certain things already, but probably certain limits have been crossed now.

"There are 20 sessions left in the season, so let's hope that at least some things will be resolved," Kubica added.

He at least praised the Williams mechanics for managing to repair his car in a short space of time following the crash in qualifying.

"The mechanics did a fantastic job, they deserve a lot of thanks for that. Unfortunately, some things do not depend on them, which is a pity," said Kubica.

"I think after Sunday morning I understand a lot more."

A Williams spokesperson was asked about Kubica's comments and defended the team.

"We didn't want to risk racing with the new wing so that we could continue to evaluate it in Mexico," the spokesperson said. "It was only ever intended for testing.

"Given the accident in qualifying, we made the right decision."