Vaz: hired solicitors to fight allegations
Writing in her autobiography, Lady Boothroyd said: "Filkin had a high profile and journalists had never enjoyed such easy access to a senior Commons official.
"Her independence and specific responsibility for policing the Register of Interests made her a prime news source."
She went on: "I did not mind her being no respecter of persons in the way she conducted her investigations.
"My worry was that MPs were put in the dock by the press on the basis of unsubstantiated accusations made against them.
"Filkin made it clear that she believed MPs who earned large sums outside the House should disclose their earnings in detail and that there were many members of the public who think it should be compulsory.
"But the rules she was paid to operate do not provide for that and she was speaking out of turn."
Here are some of the high-profile names who clashed with Ms Filkin:
Ms Filkin accused former minister Mr Vaz of going to unprecedented lengths to hinder her inquiries.
She said he failed to provide "full and accurate" answers and was unable to resolve claims that he had taken undeclared donations.
He upset her further by hiring solicitors who eventually said he would answer no more questions. Mr Vaz lost his job as Europe minister after the general election.
The former Conservative Prime Minister fell foul of Ms Filkin when she asked him to declare his large fees for foreign lecture tours.
He had been advised by Commons officials to list the speaking engagements in the register of member's interests - but Ms Filkin ruled that this was not good enough. Mr Major left the Commons after the general election.
Ms Filkin ruled Mr Mandelson should have declared the £370,000 home loan from fellow minister Geoffrey Robinson
But the standards committee refused to take action.
She also found Mr Mandelson had breached the Commons code of conduct by not disclosing all the facts to his building society when obtaining the mortgage.
Mr Mandelson was forced to resign from the cabinet.
He was later brought back as Northern Ireland Secretary but had to resign again over his links with the Hinduja brothers.
The millionaire former minister denied he had solicited an undeclared £200,000 cheque from a company controlled by disgraced businessman Robert Maxwell.
The standards and privileges committee agreed with Ms Filkin, finding that Mr Robinson had "misled us...by withholding information".
Mr Robinson was suspended from the Commons for three weeks.
The Northern Ireland Secretary was accused by Ms Filkin of intimidating witnesses.
She said his conduct "caused serious and increasing concern".
According the Guardian newspaper, she found it "quite astonishing" that many young Labour officials were being pressed by "one of the most senior politicians in Scotland" to give dishonest evidence.
Mr Reid also hired a QC who accused Ms Filkin of being "shoddy" and "mishandling" the inquiry.
This was ruled "an unwarranted attack" on her integrity by the standards and privileges committee.
But the committee overturned Ms Filkin verdict, claiming there was lack of proof. Mr Reid continues to sit in the cabinet.