If you give free rein to someone, you give them a lot of freedom to do what they want. The government continued to believe it should give free rein to the private sector in transport
one of a pair of long straps (usually connected to the bit or the headpiece) used to control a horse any means of control; "he took up the reins of government"
Journalists sometimes use the expression the reins or the reins of power to refer to the control of a country or organization. He was determined to see the party keep a hold on the reins of power