Sir Michael Spicer is the man who is charged with conducting this afternoon's no confidence vote in Iain Duncan Smith.

He will read out the result in a corridor above the Commons chamber shortly before 7.00pm tonight.

That will either confirm Iain Duncan Smith as Tory leader or spark his resignation and kick off a complex election procedure to find a successor.

12.00pm: Iain Duncan Smith faced Tony Blair during prime minister's questions in the Commons.

2.30pm: A special meeting of the 1922 Committee was held in Committee Room 14, with Duncan Smith delivering a make or break address to his MPs.

3.30pm: The no confidence ballot opened in Committee Room 14.

6.30pm: The ballot closed.

7.00pm: The result will be announced by Sir Michael Spicer, chairman of the 1992 Committee. Contrary to reports Sir Michael will announce the breakdown of the results.

If Sir Michael announces that Duncan Smith has lost the vote of confidence, the Conservative leader will be compelled to resign from his post.

A leader who has resigned is not able to seek re-nomination for the position. The party will then move on to decide a successor in a two stage process.

Candidates can be nominated to stand by two other MPs. The period for nominations is likely to conclude on a Thursday and could come as soon as next week.

If there are more than two candidates, the following Tuesday will see the first rounds of voting by MPs, who will begin the process of narrowing the list down to two candidates.

Further rounds of voting will follow on successive Thursdays and Tuesdays. When there are only two candidates left still seeking the leadership, the final decision will be handed to the party's rank and file members.

They will vote on which of those two candidates will become the new leader.

However it is not certain that party members will be given the opportunity to vote - if one of the final two candidates seeks permission to pull out of the leadership race then the remaining candidate could theoretically become leader without a wider ballot of activists.