Its the typical British 'OMG, it's so hot, we should stop all activity when the temp passes 28 degrees'. I guess Portuguese dogs don't get to go out at all May to October!
Yeah, how dare people care about animal welfare! Those bastards.
Dogs in Portugal (and other hot countries) are acclimatised to heat, but even then, they're not walked in the heat of the day. People go out first thing in the morning or last thing at night, which is what you do when you have dogs. If you can't commit to that, don't get one.
Dogs die every year in this country because people think "oh, it's not THAT hot" and take them out in the middle of the day. A young dog near here died at 9.30am back in May - no underlying health issues, he just developed heat stroke and collapsed - by the time the owner got him to the vet, it was too late and the dog died.
Not worth the risk. Keep your dog at home if it's hot. Mine is currently out in the garden but he's not running about, or walking on hot pavements, or stuck somewhere where he can't drink or get shade if he needs it.