Speaking at this afternoon's Question Time, the PM said: "We will not allow anything to eat into this very important debate."
It followed Liverpool MP Steve Rotheram attacking Dorset Conservative politician Christopher Chope who raised an objection about a previous debate on MP's own pensions, taking place on Monday afternoon, only lasting for two hours.
Mr Rotheram said: "In the real world, people wont undetsand that some people would rather debate their own pensions rather than a 22 year old injustice will want to discuss."