Another progressive and successful idea to enhance to leadership and efficiency of the "New Model Army" was the Self-Denying Ordinance of April 1647, which was proposed to Parliament by Oliver Cromwell. This removed Members of Parliament from taking any military command. In other words if you were both an MP and a commander, you would have to give up one of these jobs. This created 2 new "specializations" in Government, and separated power. One could pursue to be a politician or a commander, creating better men suited for both jobs. This was necessary during the civil war because some aristocrats in command seemed unwilling to really strike a hard blow at their own King and his forces.

Tombs, Robert. The English and their History. First Edition. Vintage Books, 2014.

Kishlansky, Mark. "The Case of the Army Truly Stated: The Creation of the New Model Army." Past & Present, no. 81 (1978): 51-74. http://www.jstor.org/stable/650363.

Image thanks to “Picture Cromwell Proposing the Self-Denying Ordinance.” Picture, oreald.com/picture2592.html.