Mohamed ElBaradei, a former head of the United Nations nuclear agency, warned: "The election of a president in the absence of a constitution and a parliament is the election of a president with powers that not even the most entrenched dictatorships have known."
The Muslim Brotherhood's presidential candidate, Mohamed Morsi, said on Thursday that the court's decision must be respected, but the leadership was hard put to maintain its collective discipline. As leading voices within it in denounced the court's decision, the Brotherhood cancelled a press conference. At least one Brotherhood politician, Issam el-Erian, went public. "If parliament is dissolved, the country will enter a dark tunnel - the coming president will face neither a parliament nor a constitution," Erian told Reuters. "There is a state of confusion and many questions."
In its decision, the court ruled that one third of the parliament had been elected illegally and that the whole body therefore had to be dissolved.
Shafiq, widely seen as a remnant of the old regime, set the tone moments after the ruling with what sounded like a victory speech in which he praised the military. "The message of this historic verdict is that the era of political score-settling has ended," he declared triumphantly.
The decision means legislative authority reverts to Scaf. The military already holds executive authority until a president is elected and it is now up to Scaf to decide when new elections should be held.
On Saturday and Sunday, Shafiq and Morsi will face each other in a presidential run-off, but Thursday's decision has now raised the prospect that the election will be overshadowed by demonstrations. On Thursday night, protesters gathered outside the court, chanting "Down with military rule".
The decision did not come out of the blue. On Wednesday a decree by the justice ministry gave members of the military police and intelligence services the right to arrest and detain civilians, an order perilously close to the conditions of emergency law which Egypt has just shed.
The court's ruling throws Egypt into a period of further political instability and uncertainty after nearly a year and a half of troubled transition under the eyes of Scaf's military rulers.
The race for the presidency has already drawn deep political lines across the country. Opponents of Shafiq see him as an extension of Mubarak's authoritarian regime while those who oppose Morsi fear he and the Brotherhood intend to turn Egypt into an Islamic state and curtail freedoms.
Intellpuke: You can read this article by Guardian David Hearst and Abdel-Rahman Hussein, reporting from Cairo, Egypt, in context here: http://www.guardian.co.uk/world/2012/jun/14/egypt-parliament-dissolved-supreme-court