DO as The Lad does, on the coldest days. He starts the car and runs it at about twice the tick over speed or so for about a minute [whilst sitting in the driver’s seat of course]. Meanwhile put the blower on the windscreen and recirculating at full chat. This way heating and reheating the same air will get it hot sooner than heating fresh charges of outside air. Put the rear window heater on. Then switch off, lock the car and return indoors and have breakfast for ten minutes or so. After that the engine will have got itself and the oil warmer by conduction mainly. Now come back and drive off to work or wherever at a reasonable speed.
DO NOT start the engine and leave it on tick over for the ten minute breakfast, then get in and drive madly away or even quietly away. One reason is that a lot of people have had their car stolen by a thief walking up, getting in and driving away. The more certain reason is that the tick over method induces vast amounts of wear in the engine.
Even at slow tick over speeds, engine pistons are still being flung to and fro in the cylinders; many shafts are whirling at high speeds and gears are rapidly meshing. These must all be stopped from wearing amazing quantities of metal away and the engine then becoming at best inefficiently petrol gulping. Eventually it will stop because the leaks through the worn parts mean that it will not have enough power even to turn itself over. The oil has a vital function in the engineering of the engines by keeping metal sufaces apart. But, when the engine is cold, there won’t be any oil there.
Why is this? Even the most modern oil will be much thicker [engineers call it more viscous] when it gets as cold as it has recently been in the UK, that’s why.
The engineers who designed your car engine set the number of cylinders and their size, the way it grabs hold of your car, the way the electronic systems will control it, the exhaust system and answered a myriad of other questions. At around this time the engineers had to design a pump and oil system to push the oil around the engine and galleries to get them to all the sliding surfaces and rolling parts. This oil system will be optimised to work best with hot oil and a hot engine because this is how it spends the great proportion of its life. Except for those few minutes on the cold days at start up. With cold, cold oil being very much thicker it is pushed towards the surfaces much more slowly and little arrives. Wear is rampant.
You can find here an excellent discussion of the how and why of lubrication. It has some American wording and technology and is a little technical. http://www.zddplus.com/TechBrief11%20-%20Internal%20Combustion%20Engine%20Lubrication.pdf
The Lad will agree with any souls who want to argue that the time of running and the engine speed that it runs at could do with being optimised to acieve the best result of minimum wear. It is so that also the optimum figures are likely to be different for every car and engine. All the same, the method of The Lad will be far, far better than leaving the car at tickover for ten minutes on its own. besides which the theft is a terrible blow to the pride. The insurance won’t pay up either.