Worse still, as we found out in Germany, then using jump cables from another car takes for ages BEFORE the car's "computer says no" changes its mind to "computer says yes". Took around 20 to 30 minutes to satisfy the computers thirst.
Many years ago I did a neat mod to one of our cars. I ran the ignition coil from a small 12V lead acid battery that was fed from the main battery via a diode. When weather was really cold and the old cranking volts dropped the coil spark output would significantly fall off and made starting difficult. The diode (or I could have used an isolation switch) worked wonders. The engine (as long as one could get a rev or so out of the main battery) fired up every time. Blinking brilliant idea and mod.
Sadly with today's vehicles this little trick won't work but for true classic car owners then it is still doable (with care).