On Thursday morning David Beckham went to spin class in Brentwood, but rather than having his nanny look after the kids, he left them waiting outside in his Range Rover -- for over an hour!

Cruz and company locked the doors to the soccer star's black SUV, and before hopping in the driver's seat, Becks told us it was fine because the air conditioning was on full blast, but this doesn't seem like the safest move. After all, it was a whopping 87 degrees in Los Angeles today! A photog on the scene tells X17online, "No one could believe what Beckham was doing. Some guys even stopped taking pictures and were just standing there, shocked."

9-year-old Cruz was sitting in the front passenger seat, and we should note that we didn't spot 15-year-old Brooklyn at the class (he usually tags along with his pops), so it's possible he was hiding in the back, but it does not appear as though there was any adult supervision, aside from the paparazzi outside.

Our photographer on the scene tells X17online exclusively:
    "David was the only man in the class, so of course all the ladies showed up during his time slot. No one seemed to mention the fact that his kids were sitting in the car out front, and one of them even defended David when we asked about it!"

We have a feeling Posh would be furious if she knew the couple's children were chilling in the car by themselves while their dad worked up a sweat --- and flirted with the ladies inside the class: