In our internal sales office, due to power requirements and stuff, they point blank refuse to switch on the air conditioning. (Even though the guy who controls it has it on in the downstairs office!)

So obviously, it's 31 degrees outside, and we're all fucking MELTING. It's also very humid..

Any advice for cooling down? Without being a retarded outkast in the office stripping off

You could get all legal on them, however might not be the best move to make. If you want to go down that path show them What is the maximum/minimum temperature in the workplace? , although it doesn't give a legal maximum temperature, it does state that in hot weather it's reasonable to have the air con on, or a fan at the very least.

Hah. I was just about to drop that link. I'd say to call them out on it, do what you have to, whatever negatives occur from it will be offset by becoming the office hero.

I would say anything above 24 at the most is unreasonable, 30 is an oven.

Actually fair point there Jay, I was thinking of the negative implications from an employers point of view, but your right, it will make him the office hero.

We don't actually have a thermometer inside, so not sure about inside temp..

Also, not allowed fans on due to "power consumption"

Its a fucking joke. They have the air con on downstairs. We aren't allowed for 3 months when the fuse board or whatever the fuck it is is re wired or upgraded.

We're here in shirt and trousers, all the women are in light vest tops and skirts (which is good.. but still!)

Also, the manager's have air con on in their offices, WTF.

Someone asked the sales manager if we can't have air con, and he just said no cos the power blah blah fucking blah.

You can either put up with it, or show them the link I sent you, and argue that it is not a reasonable working temperature. The law is on your side.

I vote that you all just slow down your work pace to a ridiculous crawl, fan yourself and complain about the heat constantly.

They'll realise it's far more beneficial to them to turn on the air con opposed to leaving it off eventually, if not they shouldn't be in management.

Fuckin stand up for yourself and your colleagues.
Sit down with your boss and make it absolutely clear (politely) that you are finding it hard to do your job anyou simply cannot work in these conditions.
They should actually respect you for being strong and standing up for what you believe in.

I've been in a similar situation just 6 months ago. I made it quite clear that something had to be done as it was making our lives a misery. I told them that if we couldn't find a compromise, I would take my skills elsewhere within the month.
Well, true to my word, two months months on I moved to my new job. Who respect me, I respect them. I could not be happier.

but did you take your skillz with you?

Alternatively you could get someone to fake passing out from heat exhaustion.

Watch management flip the fuck out when that happens. They'd be bending over backwards to stop a health and safety lawsuit.