<style..></style> should be kept inside <head> tag, i do realize, but the way i am developing a site, i am including small parts of php script for different outputs and some of those scripts use styles which I would prefer not to put in <head> tag , this is because of the fact i am using imperfect design, headers are included by main script at the begining.

Html validators gives error for putting <style></style> in side body, is it a serious issue to keep it that way or is it absolutely necessary to move any <style>s inside <head> tag?