MPs give the Outlawries Bill a first reading at the beginning of every parliamentary session, before debate on the Queen's Speech.
But it contains no serious legislative proposals, and stands no chance of becoming law.
Instead, the Outlawries Bill is about constitutional symbolism - a way for the Commons to assert its right to set its own agenda and not only the subjects included in the Queen's Speech.
The practice may date as far back as 1558, when MPs used to introduce a bill that was not included in the Royal Address regularly.
But MPs settled upon the Outlawries Bill in about 1727, and have introduced it before taking any other business nearly every year since.
The short title of the Outlawries Bill is: "A Bill for the more effectual preventing clandestine Outlawries."
The Bill has never been printed and is not presented by any Member.
In a report published in the 2002/03 session, the Commons Procedure Committee recommended that the practice should continue so that the House can "assert its freedom to consider matters of its choosing".