Tory former minister Owen Paterson is facing suspension from Parliament after being found guilty of breaching Commons lobbying rules.
The MP for North Shropshire, who denies any wrongdoing, was recommended for a 30-day suspension over an "egregious case of paid advocacy" after his lobbying for Randox and Lynn's Country Foods was investigated.
The probe by the Parliamentary Commissioner for Standards Kathryn Stone said he repeatedly lobbied ministers and officials on behalf of the two companies for which he was a paid consultant.
But Mr Paterson has angrily hit back at the investigation, describing it as "biased" and "not fair", as he blamed the probe for contributing to his wife's suicide last year.
He claimed he was "pronounced guilty by the Commissioner without being spoken to" and 17 witnesses who gave evidence to support him were "ignored".
While acknowledging that the cause of his wife Rose's suicide is unknown, he said the investigation was "undoubtedly" a "major contributory factor".
He said: "It offends against the basic standard of procedural fairness that no-one should be found guilty until they have had a chance to be heard and to present their evidence including their witnesses."
He urged Parliament to let him "prove" his case in court, insisting: "I am not guilty and a fair process would exonerate me."
He added: "Last summer, in the midst of the investigation, my wife of 40 years, Rose, took her own life.
"We will never know definitively what drove her to suicide, but the manner in which this investigation was conducted undoubtedly played a major role."
In an interview with broadcasters, Mr Paterson said he had "no doubt at all" that the investigation "was a major element" in his wife's suicide.
He said his wife believed the committee investigating him was "absolutely determined" to catch him out and whatever the findings, it would mean they "both have to resign and end our lives in misery and disgrace".
The Committee on Standards was contacted by ITV News but said it would not be commenting.
Mr Paterson told broadcasters that he is hoping to "challenge" the committee's finding in the high court, "and I will win".
Boris Johnson's spokesman said the prime minister is "mindful of the pain faced by the Paterson family" and refused to support the recommended suspension.
"The suicide of Mrs Paterson was sad and tragic and the prime minister's sympathies remain with his family following this loss."
Asked if it is right that Mr Paterson was recommended for a suspension, the spokesman said: "This is a matter for the committee themselves It wouldn't be right for me to comment beyond that."
In her report, Ms Stone found that between November 2016 and November 2017 Mr Paterson made three approaches to the Food Standards Agency (FSA) relating to Randox - a clinical diagnostics company - and antibiotics in milk in breach of the ban on paid advocacy.
He was also found to have made four approaches to ministers at the Department for International Development relating to the company and blood testing technology between October 2016 and January 2017.
And Mr Paterson was found to have made seven approaches to the FSA between November 2017 and July 2018 relating to Lynn's Country Foods.
The former Northern Ireland secretary says he was raising "very serious issues" in his lobbying, adding that "milk in supermarkets was found to contain an antibiotic residue" and thanks to him, products are "safer than before".