The perjury trial against Chris Cairns has been held together by "rumour upon rumour, sustained by a biased investigation" a Southwark Crown Court jury has been told.

Orlando Pownall QC was summing up for the defence for a second day in the trial in which Cairns denies two counts of perjury and perverting the course of justice, relating to his successful libel action in 2012 against Lalit Modi who had accused him of match-fixing.

Pownall sought to undermine a Crown case which has involved nine witnesses, including the evidence of Lou Vincent, who has confessed to match fixing, and the New Zealand cricket captain Brendon McCullum.

"We invite you to be careful to make no assumptions," Pownall said. "Beyond rumour, beyond self-motivated lies, you cannot be sure Mr Cairns is guilty. For that reason, we invite you to acquit him."

Vincent was described as the "foundation stone" of the case against Cairns. "He is someone who is dishonest, who has lied, who has lied to you," Pownall told the jury. If the jury concluded he was lying they should acquit Cairns as a consequence and the evidence of McCullum "doesn't matter".

Pownall also examined McCullum's recollections of a meeting with Cairns over dinner in 2008 in a Kolkata hotel room. McCullum's evidence, to the ICC and later the Metropolitan Police, had changed three times - in 2011, 2013 and 2014 - and was "shifting sands" he said.

Pownall said match-fixing was never mentioned in the first statement McCullum made in 2011, although the word "betting" was used time and again.

"There was a meeting and Mr Cairns has never denied it, in that hotel in Kolkata, but what was discussed in that meeting was very different from the description given," Pownall said. "What he's talking about here is betting. Not match-fixing, betting."

McCullum also did not remember that Cairns had "definitely" told him that Vincent and Daryl Tuffey were allegedly involved in match-fixing at Chandigarh Lions until after Vincent had been interviewed by the ICC in September 2013.

Pownall also invited the jury to consider why would Cairns would try to recruit McCullum to cheat, as he was a young player yet to reach the "zenith of his career" paid large sums of money in the Indian Premier League, not a "flaky individual" like Vincent who would risk his career for the sake of a "few extra dollars".

When McCullum said in a second statement that he told Kyle Mills and Shane Bond that Cairns had approached him, it referred to a meeting in Worcester the same year. He had not mentioned Kolkata.

"Does it make you wonder why didn't Mr McCullum mention the hotel meeting? Was it because himself he wasn't sure about what it was about?"

Pownall then referred to McCullum's final statement, three years later. Only then had the names of Vincent and Tuffey - who also played at Chandigarh - also been mentioned.

Pownall theorised that McCullum and Daniel Vettori, who also gave evidence for the prosecution, did not want Modi to lose his libel case because he ran IPL and his defeat might put their income at risk. "'I don't want him to lose, because that might imperil my contract. I don't want my reputation to be tarnished, was what they were thinking," Pownall said. That, he said, led them to give an account to the ICC in 2011.

Pownall said that the evidence produced by the prosecution had not shown Cairns to be a liar. "He was vulnerable, but he wasn't shown to be a liar." Pownall said. "That's not because he's some clever dick who is able to evade, he's a combative individual."

Cairns is accused of lying under oath in court when he said in that libel hearing: "I have never, ever cheated at cricket. Nor would I ever contemplate such a thing".

His co-defendant and former legal advisor, Andrew Fitch-Holland, denies one count of perverting the course of justice.