Quick Answer! - You can't...
With numerous reports of people being spotted driving along with either one or often both wing mirrors fully folded in, we explore the safety implications of such actions and try to understand how it might be possible either by accident or gross negligence to drive away in this manner.
Highway Code Rule 97:
From the very start, when you first learn to drive, a time long forgotten by many, you are initiated into driving by first checking your surroundings before driving off. This will include looking behind you to reverse and hopefully your wing mirrors to avoid curbs, pedestrians and general manoeuvring.
With new technology, it is possible, some people will use their central console screen to reverse using the camera, rely on sensor beeps to relay how close we are to obstacles, then drive away.
Once driving, mirror use becomes down to negligence as a driver. Really at this stage, there is no fathomable reason why a driver would not be checking their mirrors at least every 30 seconds to be aware of where both their car is, and to check where the other cars are ready to over or undertake.
Power folding mirrors. When things are automated we rarely take notice of them and generally assume that they work. In most cases with newer cars, locking them will fold in the mirrors and unlocking with unfold the mirrors. In some cars, however, this is not the case and even with power-fold mirrors, you may have to push a button to unfold them.
Then, of course, there are the manual mirrors that you have to actually use your hand to move, so 90s right? With these, of course, there is no excuse, you must open them to look at them, if you are not looking at them, you are endangering yourself and everyone around you.
Check your mirrors for a start...
If you are driving without checking your mirrors, ask why. Check your mirrors, before making any manoeuvre. And make sure everyone you care about does the same, you don't want to be the cause of one of the daily M25 or A2 traffic jams, caused by something as simple as not checking your mirrors and pulling out on someone and resulting in a fatal accident.