By Adam Easton BBC, Warsaw

Mr Miller ended one of his worst weeks in politics in the courtroom

He was giving evidence at the trial of a leading film producer, Lew Rywin, whose company co-produced Oscar winners The Pianist and Schindler's List.

Mr Rywin is accused of soliciting a $17.5m bribe from a newspaper publisher for concessions in a media bill.

It is alleged that he said he spoke on behalf of "people holding power".

Gripping

The scandal has damaged both the government and Mr Miller, whose political future is looking increasingly uncertain.

Mr Miller has always denied any involvement in a corruption case which has gripped the nation's attention for over a year now.

Prosecutors say Lew Rywin asked the publishers of the country's leading daily, Gazeta Wyborcza, for a bribe.

In return, they say, Mr Rywin promised to lobby the government to change a media bill, which would allow the newspaper's parent company to buy a TV station.

Mr Rywin, a famous Hollywood producer, denies the charge

Mr Miller told the court on Friday he had not sent the film producer to the newspaper company.

Mr Rywin, who is facing three years in prison, also denies the charge.

The prime minister gave evidence in what has been an extremely bad week for him.

He has seen his minority government's popularity hit a record low of just 10% in the opinion polls.

No other government in the post-Communist era has been as unpopular.

At this stage, Poland's main centre-right opposition party looks likely to replace Mr Miller's Democratic Left Alliance in next year's general elections.

Resignation calls

In a desperate attempt to shore up support, Mr Miller announced this week he would be standing down as party leader.

But the move seems to have fallen flat. One cabinet member said he should have done it earlier.

He also admitted the party is split over whether Mr Miller should stand down as prime minister.

Such a move looks unlikely before Poland joins the European Union in May.