The political agent of former MP Fiona Jones said she died from heavy drinking following the stress of a probe into her election expenses.
Fiona Jones was elected a Labour MP in 1997
Mrs Jones, 49, who died at her home, lost her seat in 1999 following an inquiry into alleged election expenses fraud, but regained it after an appeal.
Her agent Des Whicher, 81, was convicted along with Mrs Jones, who held the Newark seat for Labour.
The conviction was later overturned by the Court of Appeal.
Strain and stress
Mrs Jones failed to recover and lost her seat to Conservative Patrick Mercer in 2001.
Her husband, Chris, partly blamed the drinking culture at Westminster for her death, saying that this would not have happened had she not entered politics, adding, "she hardly drank at all before she was elected".
Mr Whicher said: "This is a tremendous tragedy and it came as a devastating shock to me because, although I realised she was not well and there were problems, I didn't know the depths of them.
"I have absolutely no doubt at all that what brought it on was the appalling strain and stress she was put under as a result of the court case and people in the Labour party - particularly locally.
"It made her time as a member of parliament very difficult."
Mrs Jones, a married mother of two teenage boys, was found dead in bed at her home in Saxilby, Lincolnshire on 28 January.
She will be cremated at Lincoln crematorium on Friday.
Mr Whicher paid tribute to her as a "committed and conscientious" politician but said she was not popular with older, more traditional members of the Labour Party following Tony Blair's landslide New Labour victory.
"She lost the next election, despite being completely exonerated by the Court of Appeal, but that didn't get nearly as much of the coverage in the press that the original trial got so the damage had been done."
No inquest is expected into her death.