He insists he believed consulting the committee was a voluntary matter - even though the code of conduct for ministers makes clear they "should" approach it. Gus O'Donnell, the Cabinet Secretary, has cleared up the confusion, telling Mr Blunkett the provision in the code is not voluntary. Mr Blunkett's critics claim he quoted selectively from a letter from Lord Mayhew of Twysden, the committee's chairman, who told him in March: "The system under which former ministers can seek our advice is a voluntary and advisory one." The rest of the sentence read: "although the ministerial code does state they should do this."
Why did he take up a post with Indepen Consulting about five weeks after leaving the Cabinet, even though the advisory committee normally expects former cabinet ministers to wait three months before taking outside jobs?
Mr Blunkett's defence is he was not aware of the rule at the time, even though he was sent a copy of the guidelines six days after resigning as Home Secretary. Some suggest he was distracted at the time over the breakdown of his relationship with Kimberly Quinn.
Why did he join the board of DNA Bioscience just two weeks before the May election when it was widely believed he would return to the Cabinet in the reshuffle?
Perhaps the biggest mystery of the affair. At the time, Mr Blunkett was working flat out to help Labour's election campaign and it was an open secret that he was set for an early return to the Cabinet. The only likely explanation is he wanted to raise some money to help fund his costly legal battle to secure access to the son he had with Ms Quinn.
Why did he not dispose of his DNA Bioscience shares after he returned to the Cabinet on 6 May to avoid any potential conflict of interest, instead of putting them in trust for his three eldest sons?
Allies of Mr Blunkett suggest that he wanted to safeguard the financial interests of his sons, having spent much of his savings on his High Court battle. He is said to have consulted them before doing so and to have won their full support. However, critics say that is another example of his private life affecting his public duties.
As DNA Bioscience might bid for contracts from the Child Support Agency, which comes under Mr Blunkett's Department for Work and Pensions, critics argue he should have cut all ties with the firm to avoid any potential conflict of interest.
How will Mr Blunkett's sons dispose of the shares and will they be able to make a profit?
It is not clear and they have not been sold yet. DNA Bioscience is still a private company and so the shares may have to be sold to another shareholder. A spokesman for Mr Blunkett insisted his family would not make a profit from the transaction. Critics will be looking for firm evidence that this promise is kept.
Why is Tony Blair allowing Mr Blunkett to remain in his cabinet post even though he admits breaching the code of conduct?
Downing Street says the PM believes Mr Blunkett made a mistake but did not deliberately flout the code and has acted with integrity by admitting his error and selling his family's shares in DNA Bioscience. There have been calls for an independent watchdog to police the behaviour of MPs.
- More about: