light-coloured or fluorescent clothing in daylight
reflective clothing if you have to ride at night or in poor visibility
51. Rules about animals - Horse riders
At night. It is safer not to ride on the road at night or in poor visibility, but if you do, make sure you wear reflective clothing and your horse has reflective bands above the fetlock joints. A light which shows white to the front and red to the rear should be fitted, with a band, to the rider's right arm and/or leg/riding boot. If you are leading a horse at night, carry a light in your right hand, showing white to the front and red to the rear, and wear reflective clothing on both you and your horse. It is strongly recommended that a fluorescent/reflective tail guard is also worn by your horse.
52. Rules about animals - Riding
Before you take a horse on to a road, you should
ensure all tack fits well and is in good condition
make sure you can control the horse
Always ride with other, less nervous horses if you think that your horse will be nervous of traffic. Never ride a horse without both a saddle and bridle.