If, when walking, you throw you starboard leg across your body and your port leg (sequentially, of couse) to port, you will turn to port. If you wish to turn to starboard, just continue this process until you have completed the necessary portion of a complete circle and are facing your desired heading, then revert to moving your legs only in a fore and aft direction to return to a straight course.
This is known as bearing away and gybing around. There is an alternative course-changing method known as tacking, but this can cause serious injury, expecially on Oxford Street at this time of year, and so is not recommended.
You omitted to mention the effects of over-indulgence in Xmas beverages. Experience tells me that control of self steering can become erratic or even fail altogether when blood in alcohol level reduces significantly.
Then it's time to revert either to bringing-up all standing (try and do it in the gutter, while holding station on a lamppost or parking meter) or steering by the ancient art of cannoning - sometimes known as the in-off, or the ricochet effect.
With all due respect - and there's bucketloads of it, I feel that the forum would possibly appreciate a fuller description of the advice required - that given has been excellent so far and got me home nicely last night.