On Wednesday Sir John Chilcot will write a letter to the Prime Minister. In it he will say his Iraq inquiry will not be able to report until after the election.
Sir John is expected to say the delay has been caused by those named in his final report.
They have an opportunity to respond to any criticism made of them and that process seems to be holding up the publication.
Last year, the Prime Minister expressed an interest in the Inquiry reporting 'before Christmas'.