Pedestrians have a right of way over motor vehicles only at official pedestrian crossing points such as Zebra crossings. However, right of way is a law in traffic that is used to determine who has the right to use the conflicting part of the road and who will have to wait until the other does so. Here, signs, signals, markings and other features are often used to make priority explicit.
These might be relevant OP
https://www.gov.uk/rules-pedestrians-1-to-35/general-guidance-1-to-6
https://www.gov.uk/using-the-road-159-to-203/road-junctions-170-to-183