He failed to lead
In the end, he had no choice.
Denied that debate yesterday, MPs from all sides expressed their lack of confidence in him in the only way left open to them - telling him to his face that he was part of the problem and not the solution.
The Speaker's position depends on his unquestioned authority over the House of Commons. Michael Martin's authority finally died yesterday.
Some will complain that he has been made a scapegoat for the failings of individual MPs.
Others will insist that this Glaswegian sheet metal worker was the victim of class-based prejudice and snobbery.
There is some truth in both those charges.
However, the reason he has been driven from office is much more simple than that. At a time when the Commons desperately needed leadership, he failed to lead.
He failed to see this crisis coming.
He presided over the system which encouraged MPs to fiddle their expenses or to claim them to the max.
He wasted time and money on fighting calls from taxpayers to see what MPs were doing with their money.
He did little to stand up to those MPs who resisted reform.
His reaction to the publication of MPs' expenses was to call in the police and to attack those MPs who criticised him, rather than using his position to apologise to the country or to speak to MPs on behalf of the electorate.
Michael Martin acted too often as the shop steward of the Commons and too rarely as if he held one of the highest offices in the land.
When the Commons was exposed as indulging in old-style Spanish practices, the shop steward simply had to go.