Is is a good time of year to prune your apple and pear trees as they are now dormant. Trim back to one or two buds, thin out branches that are congested or rubbing against other branches. By doing these jobs you will increase the light and air flow through the tree. Remove any "mummified" fruits still hanging on your trees as these can be a source of rot going into the new season.
Despite it being January there may still be plenty to harvest, Leeks may well be standing ready but if a sustained freeze is expected then you can dig a few up and heel them in to dug ground. Parsnips and swedes in the ground can also come up when you are ready, but until then cover them over with fleece or straw to stop them freezing solid into the ground. The cabbage family should be providing some sustenance and beet leaves (perpetual spinach) and chards will be available. On a sunny day it is worth emptying your potato sacks and check for any that are starting to rot before it spread
Protect tender plants
Tender perennials such as Cordylines and Fuchsia should be kept out of the frost, so bring them into the green house or conservatory.
Brush heavy snow off trees
If you get a heavy snow fall then brush shrubs and conifers with a broom to prevent branches getting damaged.
If the ground is now frozen finish off any digging over you still need to do.
Thoroughly clean and oil your loppers, secateurs, and other hard worked tools so they’re fit for another years maintenance in the garden. Start off by giving them a good scrub with some hot soapy water and leave them to dry thoroughly before wiping over with an oily rag to stop them going rusty.
If you dont have any (or enough) then this is a good time to plant in the green especially if a friend of neighbour can provide them to you.