British elections are held on a Thursday for the following historical reasons:
  • Friday was traditionally the day when the working man got paid; the money in his pocket might embue him to look uncharacteristically favourably upon his employer if the election were held then
  • On Sundays all "decent folk" went to church, where they might be over-influenced by the preachings of their vicars
Thus Thursday was chosen as the day furthest from the meddling influence of the Church (those pesky religious types, preaching peace and love and other such socialist doctrines), yet before a pocketful of shillings could swing popular opinion in another direction. As with many things which are now tradition this reasoning could be just so much bullshit.

As to those who are disbarred from standing as a Member of Parliament, it is quite a small list:

  • Undischarged bankrupts
  • Peers of the Realm
  • The mentally ill
Criminals are not disbarred and there have been notable occasions when prisoners in jail (in particular members of the IRA) have been elected to Parliament.