Highway code rule 163 – Overtake only when it is safe and legal to do so. You should give motorcyclists, cyclists and horse riders at least as much room as you would when overtaking a car (see Rules 211-215)
Highway code rule 212 – When passing motorcyclists and cyclists, give them plenty of room (see Rules 162-167). If they look over their shoulder it could mean that they intend to pull out, turn right or change direction. Give them time and space to do so.
Highway code rule 213 – Motorcyclists and cyclists may suddenly need to avoid uneven road surfaces and obstacles such as drain covers or oily, wet or icy patches on the road. Give them plenty of room and pay particular attention to any sudden change of direction they may have to make.