Media playback is unsupported on your device Media caption BBC's John Sudworth outside the court, which journalists are not allowed in: Bo Xilai said "she has changed, she's gone mad, she always lies"

Former top Chinese politician Bo Xilai has dismissed his wife's testimony that implicates him in corruption, claiming she is insane.

Mr Bo's wife, Gu Kailai, testified that a rich Chinese entrepreneur bought gifts for the family to gain favours.

Gu Kailai was herself convicted last year of the murder of British businessman Neil Heywood.

The scandals involving Mr Bo's family, which used to be one of the most elite in China, have captivated the country.

Despite the fact the trial is thought to have a predetermined outcome, Mr Bo has launched an unexpectedly vigorous defence.

Analysis The first day of Bo Xilai's trial certainly yielded some unexpected fireworks. Mr Bo mounted a surprisingly spirited defence of the charges that have been levelled against him so far. However, many in China are waiting to see if the second day of the trial will deal with something far juicier: the abuse of power charges. The former top official is accused of exploiting his lofty position for his own benefit. He is alleged to have ordered a cover-up of his wife's involvement in the murder of British businessman, Neil Heywood. When dealing with corruption charges, the court prosecutors relied on the testimony of Bo Xilai's wife, Gu Kailai, and the wealthy businessmen who reportedly greased the palms of the powerful Mr Bo. The authorities in charge of the trial have taken pains to demonstrate that Mr Bo is receiving a fair, open hearing. But when dealing with the abuse of power charges, how much will they allow prosecutors to reveal about the inner workings of the Party itself? What Chinese make of trial

Analysts say the court hearing is as much about getting rid of a popular politician as it is about criminal wrongdoing - and Mr Bo is widely expected to be found guilty.

The trial is set to continue for a third day on Saturday, Xinhua news agency reported.

'Unstable mental state'

Mr Bo, who used to be the Communist Party chief in Chongqing, is accused of bribery, corruption and abuse of power.

Video footage and written testimony from his wife was posted on the court's official microblog.

In it she said she felt Neil Heywood was a threat to her son, Bo Guagua.

She also spoke of receiving gifts from a Dalian entrepreneur, Xu Ming, from whom Mr Bo is accused of taking bribes.

On Thursday Mr Bo denied bribery, saying he had been forced into admitting it to prosecutors.

He also rubbished testimony from witnesses including his wife. Of her testimony, he reportedly said: "In her unstable mental state, prosecutors put pressure on her so she would turn on me."

Image caption Gu Kailai appeared relaxed and lucid on the video

Foreign media are not being allowed into the trial, which is taking place in the city of Jinan in Shandong province.

But the Jinan Intermediate People's Court is posting updates and relevant testimony on its official microblog in Mandarin, excerpts of which have been translated by the BBC.

It remains unclear, says the BBC's Celia Hatton in Beijing, whether the events as described by the court constitute tightly-scripted political theatre or an unexpectedly colourful legal showdown.

But Steve Tsang, professor of Chinese studies at Nottingham University, said: "It would be inconceivable if the verdict has not already been agreed."

"The trial of someone as important as Bo Xilai is not something that could be left to the judges presiding over it," Mr Tsang said.

'Ask Xu Ming'

[The authorities] have mounted a display of openness while keeping risks under control in a highly skilful manner Zhang Zhi'an, Journalism professor, Sun Yet-sen University Transparency or theatre?

Mr Bo's downfall was seen as the biggest political shake-up to hit China's ruling elite in decades. In February 2012 his police chief, Wang Lijun, fled to the US consulate in Chengdu amid an apparent fall-out with Mr Bo.

Shortly afterwards, Chinese authorities announced that they were reinvestigating the death of Mr Heywood, who died in a Chongqing hotel in November 2011.

Gu Kailai has since been jailed for the murder of Mr Heywood - a crime she carried out, state media say, because of differences over a business deal.

In written testimony to the court, she said she believed that the personal safety of her son "was under threat".

"In the second half of 2011 Guagua made a video call to me on his iPad telling me that Neil Heywood threatened him," she said. Subsequent e-mails between the two scared her, she said.

"After the video call I was very worried which led to the 15 November crime [when Neil Heywood was killed]."

Written testimony from Patrick Devillers, a French architect, meanwhile, pointed to conflict between Gu Kailai and Neil Heywood over a financial deal related to a villa in France that has been a focus of the bribery charges.

Bo trial: Day one Indictment says Bo took bribes from Xu Ming and Tang Xiaolin, either directly or via his wife and son; abused his power in connection with the murder of Neil Heywood; and embezzled 5m yuan of public funds from the Dalian government in 2002

Bo calls on the judge to try the case "fairly and justly according to the law of the country"

Bo denies taking bribes from Tang and Xu, calling Tang a "crazy dog snapping at things for reward" and cross-examining Xu on the stand

Bo dismisses his wife's testimony - which related to cash held in a safe - as "ridiculous"

Xu tells the court he bought a villa for Gu Kailai and paid Bo Guagua's credit card bill Trial transcripts - day two Key players Timeline

It was paid for by Xu Ming, the court heard on Thursday, one of two men from whom Mr Bo is accused of receiving bribes totalling 21.8m yuan ($3.56m; £2.28m).

In her video testimony Ms Gu said it was true that Xu Ming had bought things for her and her son, Bo Guagua.

"When we need to book a flight, family members know to ask from Xu Ming," she said.

Bo Xilai, responding to his wife's testimony, is reported to have said: "How much credibility is there are about Gu Kailai's testimony, and her written material? Gu Kailai has changed and she became crazy and lies all the time."

It is not clear how long the trial will last. Mr Bo is the last major player in connection with the Neil Heywood case to face judicial proceedings.

His son, Bo Guagua, remains in the US, where earlier this week he said any verdict would carry no moral weight if his "well-being has been bartered for my father's acquiescence or my mother's further co-operation".

There has been speculation that both Bo Guagua's parents agreed to demands from Chinese officials in return for a guarantee that he would not be pursued.

Bo Guagua also said his mother had been unwell since 2006, following a "sudden collapse of her physical health".