Former New Zealand captain Brendon McCullum believes his ex-teammate Lou Vincent should been shown clemency by the ECB after helping the authorities with a "rare and critical" insight into the "pernicious influence" of match-fixing in cricket.

In July 2014, Vincent was banned for life by the ECB after admitting to having breached the anti-corruption code. Vincent released a statement saying, "My name is Lou Vincent and I am a cheat."

In October last year, Vincent was one of the three key witnesses, along with his ex-wife Eleanor Riley and McCullum, who gave evidence in the perjury trial against the former New Zealand allrounder Chris Cairns at Southwark Crown Court. After lengthy deliberations in a nine-week trial, the jury acquitted Cairns of perjury and perverting the course of justice. Justice Sweeney, the presiding judge, had told the jury to treat Vincent's evidence with care, given his self-confessed reputation as a match-fixer.

However, McCullum said that, while he could not condone in the slightest Vincent's fixing activities, he admired the courage that Vincent had shown in standing up as a witness in the Cairns trial and shining light on the murky world of match-fixing in cricket.

"I played with Lou for a number of seasons. As will have become apparent during the course of his testimony in the Cairns' trial, Lou has his demons," McCullum said while delivering the MCC Spirit of Cricket lecture on Monday at Lord's.

"He was always a vulnerable character; there are many similar characters who play the game. While loathing the fixing activities Lou took part in, I have nothing but admiration for him for the way in which he accepted responsibility for his actions and acknowledged guilt. I also think he demonstrated remarkable courage in giving evidence against Cairns.

"The insight that Lou was able to provide into the dark and sinister world of match-fixing was, I think, invaluable. It would have been very easy for Lou to say nothing - to refuse to co-operate - but instead he laid his soul bare at considerable personal cost."

If the anti-corruption units wanted to encourage vulnerable players like Vincent to report approaches in the future, McCullum believes that such players need to believe they will be treated with leniency if they dare to speak out.

In particular, McCullum sympathised with Vincent's predicament after receiving 11 life bans from the ECB that forbid his involvement in the game at any level.

"Perhaps the worst part is that Lou is unable to go to a cricket ground anywhere in the world. He can never watch his children play at any level. I struggle with the severity of this when a player has co-operated fully and accepted responsibility.

"While it was reported that Lou had agreed to the 11 life bans, I suspect that sitting in New Zealand without a dollar to his name, he was unable to do anything else. In the criminal law in New Zealand a defendant is given some clemency for co-operation and entering a guilty plea. It seems to me that Lou did not receive any such acknowledgement but, rather, had the book thrown at him.

"I raise this issue because if we are to expect players to feel able to come forward and confess all, then there has to be some recognition of this," McCullum added.

"Many of the players who become involved in match-fixing in the way that Lou did will be weak or vulnerable; it is well known that the people who seek to engage players in this way will look for players of a similar disposition. If players co-operate with the authorities and provide the game with a rare and critical insight into the workings of this pernicious influence, then there must surely be something that can be done beyond giving them the maximum ban available.

"I have no doubt that the ECB's severe punishment of Lou has robbed the game of a golden opportunity to have him provide education to players, something I feel could have made a difference in the future. Further, it ignored his extreme vulnerability in a callous way.

"Unless players can have confidence in the authorities and their processes, then I am sorry to say that the game will be the loser. Similarly, it is vital that players found guilty of offences having acknowledged wrongdoing are shown a degree of clemency - failing which there seems to be very little incentive for them to come forward."