However, following exhaustive (and exhausting) testing at the IT Donut office today, we can report that this USB fan does a reasonable job of circulating air while you're at your desk, creating a microclimate that feels at least a little more comfortable.
What's more, it's available for a stunningly-cheap £3.42 from Amazon. And unlike your local DIY store - which is likely to have run out of fans some time last week - plenty of these USB fans are available for fast delivery. They're perfect for the hottest day of the year so far.
There are plenty of other options for cooling down, of course. Try putting ice in your drink, using mobile broadband to work from a cooler location (perhaps a local park?) or simply popping out to the local swimming pool at lunchtime.
How are you keeping cool in the heatwave?