Denis MacShane cited far right opponents in him quitting as an MP and stand down from his fight against anti-Semitism in Europe.
The former Rotherham MP quit his seat following a damning verdict found he had fiddled taxpayers out of more than £12,000 to fund train travel around Europe.
Ex-Europe Minister MacShane was initially banned from parliament for 12 months, but his became impossible after the Labour party admitted his careers "was effectively over." Leader Ed Miliband said he did the "right thing" by standing down.
In a statement, MacShane said: "In the light of the Parliamentary Commissioner's decision, supported by the Committee of Standards and Privileges, to uphold the BNP complaint about expenses claimed in connection with my parliamentary work in Europe and in combating anti-Semitism.
"I have decided for the sake of my wonderful constituency of Rotherham and my beloved Labour party to resign as an MP.
"I have been overwhelmed by messages of support for my work as an MP on a range of issues but I accept that my parliamentary career is over.
"I appreciate the Committee's ruling that I made no personal gain and I regret my foolishness in the manner I chose to be reimbursed for work including working as the prime minister's personal envoy in Europe."
Earlier in the day, MacShane issued a statement accusing the far-right party of seeking to wreck his career. BNP stalwart Richard Barnbrook mounted the complaint which led to the investigation by Parliamentary Commissioner - whose report buried his parliamentary career.
"I am shocked and saddened that the BNP has won its three-year campaign to destroy my political career as a Labour MP despite a full police investigation which decided not to proceed after investigations and interviews. I am glad the committee notes that there is no question of personal gain.
"Clearly I deeply regret that the way I chose to be reimbursed for costs related to my work in Europe and in combating antisemitism, including being the prime minister's personal envoy, has been judged so harshly."
Personal tragedy was what triggered his behaviour, claimed MacShane. The death of his daughter in a sky-fall accident and divorce from his wife meant he paid no attention to paperwork, such as expenses forms.