Egypt's military took responsibility for state security today in the run-up to the contentious December 15 constitutional referendum.
President Mohammed Morsi's decision means that the army will police potentially explosive rival protests in Cairo tomorrow.
Soldiers have been given powers of arrest alongside police officers.
The police have been undermined in recent weeks as they have failed to quell the violence sparked by November 22 presidential decrees that placed Mr Morsi beyond judicial oversight.
He has since rescinded the decrees as an apparent concession but opposition activists say that they have already served their purpose of pushing through the draft constitution.
The proposed charter enshrines Islamic law and fails to meet the expectations of the secular civil rights campaigners who helped to topple former president Hosni Mubarak.
Opposition party the National Salvation Front has called for a mass rally in Cairo's Tahrir Square tomorrow to force Mr Morsi to scrap the constitution and elect a more representative constitutional assembly.
Government supporters claim that the party is part of a conspiracy to bring back elements from the Mubarak regime and have called for their own protests, sparking fears of violent street clashes.
The National Salvation Front has still not made clear whether it intends to boycott or campaign for a No vote, but it said in a statement that it does not recognise the draft because it "does not represent the Egyptian people."
Meanwhile, Mr Morsi also suspended a planned tax increase on goods such as cigarettes and beer.
Fire Minister Brandon Lewis probably had a fair idea what Sir Ken Knight would deliver when he asked him to conduct an "independent" report into fire and rescue services in England.
As LGBT activists worldwide celebrate anti-homophobia day we are reminded of prevailing prejudice
Bradford has seen the launch of a new campaign to battle the sources of child sex exploitation - and combat far-right bids to make it a racial issue