I can't think of any reasons why a properly adjusted drum brake would be slower than a disc brake. The brake lines are the same, and they are filled with brake fluid which can be pressurised in an instant.

We have lot's of Skoda cars in Norway with drums on the rear, and ESP is delivered on all cars except if the absolutely cheapest ones which no one buys. The system works just as well on the cars with drum brakes

i think the issue comes from drum brakes retaining heat and the amount ESP can apply the brakes causing possible overheating.

I think there is isn't an issue at all with combining drum brakes and ESP. Even the early EDL / electronic diff. lock systems had a "counter" which counted how many brake cycles that had been used to keep the wheel with no traction from spinning, and cut out the system when overheating of the brakes could be an issue.

I have driven a lot of ESP cars in extreme conditions both with discs and drums on the rear, and the use of the brakes to keep the car going in the intended direction is never long on each wheel.

An emergency stop from say 70 mph is much more of a load on the brakes if compared to correcting a slide when going at the same speed on ice.

Drum brakes from 70mph don't half get smelly though LOL - but I know that's not the point of the original post

Thanks for the info though - was interesting to read up a bit more about it