The planet Mercury is definitely mercurial. It’s as hard to catch as quicksilver. But the closest planet to the Sun is in the evening sky right now, in the south-west just after sunset, so early January 2022 is a good time to look for it. Mercury is at its farthest from the Sun on 7 January, but it’s still around for a few days after that date.
You’ll need a good clear sky and a low horizon to see it, and because the sky is still bright at that time you’ll have to search carefully. Just as you are about to give up you will probably spot it as a starlike point, and once you’ve seen it it becomes easier to find it again. Saturn is also appearing in the evening sky in the same direction, although quite a lot fainter, so you may spot that as well. Binoculars would definitely help you to find both planets.
Where to look
Look to the south-west about 40 minutes after sunset or a bit later, in the brightest part of the twilight sky where the Sun has set. It’s much closer to the horizon and to the right of Jupiter, which is the bright planet in the south-west at the moment. The time of sunset depends on where you live in the UK, varying from about 16:10 in the London area to 15:40 in northern Scotland. But don’t leave it too long – there’s only a window of opportunity about 20 minutes long in which to view it.

Mercury is moving closer to the Sun as seen in the sky evening by evening, and will become too low to be seen easily by about 16 January. The next opportunity to view it in the evening sky will be at the end of April.
Viewing tip
If you have a phone app that shows the stars, and knows which way it’s pointing, this is the time to use it! It will show you exactly which direction to look in, and how high Mercury is above the horizon. But even then, it won’t be all that easy.