I would never pour water of any temperature on an iced-up car. It would do more harm than good, not least from coating the ground around the car with yet more ice.

First, start the car. Turn on the rear-window defroster and crank up the heater to full blast, ensuring that the vents are set to blow on the inside of the windscreen and side windows. Then get out your ice scraper and set to work, starting on the rear window and proceeding around the car, doing the windscreen last. Let the warmth inside the car weaken the ice and chop it off with the scraper.

If you don’t have an ice scraper, you should not be driving in winter. You should also have a proper snow-brush with a handle long enough to allow you to clean the roof.

Why clean the roof? Because the snow hat will eventually slide off and block your back window if you’re lucky. If you’re not lucky, it will fly off at speed and splat all over the windscreen of the car behind you, blinding the driver.