Dr Rowan Williams is due to speak as the Church's national assembly gathers after the legislation failed to gain the necessary two thirds majority amongst lay members.
His statement will come after an emergency meeting of the Church of England bishops following the narrow defeat.
More top news
Philippa has Monday's weather update for the east
Philippa has Monday's weather update for the west
A team of six crew members, including one from Oxfordshire, have completed a year-long experiment in Hawaii which mimicked life on Mars.