Deputy Prime Minister Nick Clegg has pledged the introduction of a five year fixed term parliaments will have a "profound effect" and lead to greater stability in the political system.
The Fixed term Parliaments Bill faces its second reading in the House of Commons this afternoon.
"Establishing parliaments of fixed-terms is a straightforward, but fundamental, change in our politics. It is a simple constitutional innovation, but one that will have a profound effect," the Deputy Prime Minister said.
"For the first time in our history, the timing of general elections will not be a plaything of governments and Prime Ministers will no longer have the power to go to the polls at a time of their own choosing. Instead, there will be greater stability in our political system and people will know exactly how long a parliament can be expected to last.
"There may be exceptional circumstances in which it would not be appropriate for Parliament to continue to run for its full term. When there is a need to seek an earlier dissolution, that will be for the House - not the Government - to decide."