When I worked in the Tower or Radar at Manch, I wore jeans and a polo shirt, IF however, I was working in AIS/Flt Briefing, I wore slacks and a smart short sleeved shirt......
because I was on Public view
If one worked at PATCC in the '60s/70s and you arrived without a tie, you were sent home [pay docked] to get one...... times have changed