Here is how some of the key allegations against Home Secretary David Blunkett relate to the codes of conduct that apply to ministers and MPs:
Allegation: That Mr Blunkett used his position as home secretary to facilitate the granting of permanent residency for Leoncia Casalme, his then lover's nanny.
What the Ministerial Code, the prime minister's code of conduct and guidance on procedure for ministers, says:
58. "Ministers have a duty to give fair consideration and due weight to informed and impartial advice from civil servants, as well as to other considerations and advice, in reaching policy decisions; a duty to uphold the political impartiality of the Civil Service, and not to ask civil servants to act in any way which would conflict with the Civil Service Code; a duty to ensure that influence over appointments is not abused for partisan purposes; and a duty to observe the obligations of a good employer with regard to terms and conditions of those who serve them.
Civil servants should not be asked to engage in activities likely to call in question their political impartiality, or to give rise to the criticism that people paid from public funds are being used for party political purposes.
Allegation: That the home secretary asked civil servants to look at the visa application.
What the Ministerial Code says:
113. Ministers must ensure that no conflict arises, or appears to arise, between their public duties and their private interests, financial or otherwise.
114. It is the personal responsibility of each minister to decide whether and what action is needed to avoid a conflict or the perception of a conflict, and to defend that decision, if necessary by accounting for it in Parliament.
The role of the permanent secretary is to ensure that advice is available when it is sought by the minister, either by providing it personally, drawing on precedent and if need be other parts of government including the Secretary of the Cabinet, or by securing the services of a professional adviser (which should be arranged through the Central Secretariat of the Cabinet Office). In cases of serious difficulty or doubt the matter may be referred to the Prime Minister for a view. But ultimately it is the responsibility of Ministers individually to order their own private lives in such a way as to avoid criticism, and the final decision about what action to take to achieve that is theirs.
Allegation: Mr Blunkett gave Mrs Quinn two first-class rail tickets in August 2002 which are thought to have been intended to aide his work as an MP.
But MPs are only allowed to give travel warrants to their spouses. "Partners" do not count. This is the rule Mr Blunkett admitted he had misinterpreted when he announced he would pay back Mrs Quinn's £180 train fare.
What the Green Book (which sets out guidelines for MP's use of allowances and expenses) says:
The following are allowable provided that the travel was undertaken on Parliamentary duties:
You cannot claim for:
Subsistence (except for European and extended travel)
- Standard travel: Travel by the recognised direct route between any two of the following three points: Your main home, Westminster, the constituency.
Constituency travel: Travel within the constituency, and travel between the constituency and local or regional offices of government departments, offices of local authorities, or the regional or Parliamentary assembly.
- Extended travel within the UK. (This requires advance authorisation.) Crown dependencies are not allowable.
Travel fares for anyone other than you, your staff and family as set out in the guidance which follows
You may however carry passengers with you in your car
Congestion charges, tolls, and car parking (An allowance for these is included in the car mileage rates.)
Costs of leasing or purchasing a vehicle (The car mileage rates include an element to cover purchasing costs)
But the key Green Book passage relating to Mr Blunkett is this one:
You will be asked for the names of your spouse and children, so that we can provide books of warrants. Please let us know of any relevant changes, for example any changes to your marital status.