xkcd #3232: Countdown Standard
Title text:
Anyone who is caught counting 'three ... two ... one ... zero ... GO!' will be punished with a lifetime of eating only ISO standard food samples.
Transcript:
Transcript will show once it’s been added to explainxkcd.com
Source: https://xkcd.com/3232/
I'm from the UK too and I've definitely heard things like:
"Yeah, I saw her this thursday"
If you used 'last thursday' in that case it would still obviously be understood, so I'm not sure it really matters. The importqnt distinction is between 'this' and 'next' thursday.