To all the posters suggesting wearing 'nice airy maxi dresses' etc. You do realise that not all women want to dress like that?
I barely own any dresses, and not of that type. They're not me, and I'm not going to start wearing them to appease someone's idea of appropriate. We don't all aspire to look like respectable Tory wives from Tunbridge Wells.
Unless there is a clear uniform provision, I'll want to wear whatever of my own clothes, of my own style, that allow me to feel comfortable in hot weather.
And yes, that includes vests in the office. I'm mid 40s, perimenopausal and run hot, and I'm much happier if my clean, deodorised armpits are allowed to air, rather than soaking into underarm material of any sort.
And I work in a corporate environment where, shock horror, men and women can wear shorts/tshirts/vests, and some women above knee skirts too.
In order to stop policing women's bodies we need to actually stop policing women's bodies.