The judge in charge of Cairns' perjury trial, Justice Nigel Sweeney, pointed to the fact that McCullum said he was "shocked and stunned" by the April 2008 conversation with his friend.
"You want to ask yourself in due course whether being shocked and stunned was a reaction to an innocent conversation about spread betting," Justice Sweeney said to the jury in summing-up.
The judge said the jury needed to decide whether McCullum's account was deliberately changed to serve his own interests, as the defence suggested.
Or were the changes because McCullum was asked questions more carefully in his second and third interviews, or innocently recalled more details.
"It's a matter for you," he told the jury.
Below are the excerpts of McCullum's statements read in the Southwark Crown Court.
First statement, to the ACSU, February 17, 2011
This statement made by me is the truth to the best of my knowledge and belief. I make it known that I have not wilfully stated in it anything that I know to be false or do not believe to be true.
Questioner) I understand that you wish to make a statement in relation to a discussion you had with Chris Cairns during the IPL in India 2008?
Respondent) Yes.
Q) Can you tell me why you want to make this statement?
R) The conversation I had with Chris has been sitting uneasily with me for some time and it is time to pass on the conversation.
Q) In your own words can you tell me what happened?
R) It was about four days before the first game of the very first IPL series and I was staying at the ITC Sona Kolkata and Chris rang me and asked me if I wanted to come around to his hotel to see him, which is standard practice between former teammates.
He was staying, I think, at the Taj Hotel. I went around to his hotel and we ordered some dinner and cracked open a bottle of wine, he was staying in a suite at that hotel.
We had general conversation and then after about half an hour he asked me if I knew anything about spread betting.
I told him that I didn't. I actually thought he was taking the piss a little bit. He grabbed a piece of paper and pen and showed me how it all worked, he spoke about splits of overs and he told me that everyone was doing the betting.
He was telling me you could make a great deal of money, he indicated you could earn 80,000 to 200,000 per game.
I asked him had he been doing the betting and he told me he had never done it in an international match.
I further asked him how do you get the money back to NZ and he told me that you didn't you brought property in Dubai.
At this stage I was really shocked. Chris was a very senior member of New Zealand cricket and a senior member of the New Zealand cricket side. When he spoke to me about betting it really shocked me, it really shocked me.
We generally discussed the betting and I was probably naïve at the time and in hindsight I should have told him there and then that I was not interested.
He told me to think about it and he would ring me in a few days. I then went back to my hotel.
He did ring me a few days later and I told him clearly it was not for me. He said, that is fine mate. Just keep in mind that his conversation never happened.
Even his last comment of the conversation, never happened, concerned me. It was just like he would move on to the next player.
At the conclusion of the IPL I had to rush to England to rejoin the NZ team who were playing a warm-up game prior to the England series.
He rang me and again asked me if I had changed my thoughts in relation to the betting. I indicated to him that I hadn't.
Q) Can you tell me why you didn't contact the ASCU office and inform them of the approach?
R) The approach by him really shocked me. He is a very highly respected member of the New Zealand cricket community and for him to ask me to do this just stunned me.
He was a friend and a person I thought I could count on in a hard time. So I decided to keep the conversation to myself. I knew it was going no further with me so I figured I had quashed the issue.
The conversation I had with him has sat with me very uneasily for some time. When I had the education discussion with you [John Rhodes] I knew it was time for me to tell you what happened and that is why I made the statement.
Q) Is there anything else you wish to tell me about this matter?
R) No that is all.
Second statement, to the ACSU, November 27, 2013
I have been shown a copy of this statement that I made and gave to John Rhodes on 17 February 2011 concerning an incident involving Chris Cairns and myself.
I take this opportunity to expand on that statement. The only other people I've mentioned this matter to is Daniel Vettori, Kyle Mills, Stephen Fleming and I think I also spoke to Leanne McGoldrick about this who was my manager for a while.
I was really shocked as I saw Chris as a good friend and it totally confused me.
Chris said that everybody was doing this in games. He said the big boys in international cricket were doing it and that he didn't want me to miss out on it.
I'm sure that he mentioned some names to me, but I really cannot remember those names now but I seem to think Chris mainly mentioned Asian cricketers.
Chris told me he had a good group working for him in the ICL and I understand this to mean fixing for him. It was my opinion then as it is now Chris was actively concerned in fixing and I got this opinion we were having where I believed he was asking me to do the same thing for him in the IPL as others were doing in the ICL.
Chris viewed international matches in a different way to how he saw the Asian league games.
This whole conversation was as strange feeling for me as I had convinced myself that the first conversation had not really happened because the whole business was so hard for me to accept.
After this I had very little contact with Chris. I spoke to him once briefly in Christchurch and then after that I met him in India when in 2009 the majority of the team were invited to a function.
This was in Bangalore and Chris had told the person who arranges things for him there, Joseph, to arrange a big party for the New Zealand team, part of which was a fashion show.
I was also aware that Chris became involved in doing business with a diamond dealer who was based in Dubai but I'm not exactly sure of what this business was.
Third statement, to the Metropolitan Police, March 17, 2014
On 4 Feb 2014 I met with United Kingdom police officers from Metropolitan Police Service and was asked again about my knowledge of Chris Cairns and match-fixing in cricket.
I told them what I had told John Rhodes although I would like to add the following details to my previous statements.
As I stated I was staying in the ITC Sona in Kolkata in 2008 when I received a call from Chris Cairns asking to meet me in his hotel.
When Chris called I was having a beer with the then Australian cricket captain Ricky Ponting.
Chris told me he had a business opportunity to discuss with me. I told Ricky of this and he said something like sounds interesting.
I've not discussed this with Ricky since, I have no idea whether he will remember this conversation.
I am aware of the recent press coverage in December 2013 linking the names Chris Cairns, Daryl Tuffey and Lou Vincent to match-fixing.
However I can confirm that Chris Cairns definitely mentioned these two names to me as being involved in 2008.
I haven't ever spoken to Lou or Daryl about this. Chris Cairns also said to me I don't want you to miss out, which I took to mean miss out making money from the fixes.
He said that he had asked me to get involved because he knew Dan and Jake didn't have the balls, meaning our New Zealand teammates Daniel Vettori and Jacob Oram.
- By Jared Savage in London
