How to Prune bean (runner) 'Red Rum'?
No pruning required

bean (runner) 'Red Rum' · Phaseolus coccineus 'Red Rum'
Sow seed 5cm deep, either directly outside in early summer, or under glass in early spring then plant out in early summer, after all danger of frost has passed, in full sun and in well-drained but humus-rich, moisture-retentive, preferably near-neutral soil, provide support such as hazel poles or bamboo canes, keep well-watered, and pick pods regularly, before the seeds swell, to ensure a continuous crop; for more advice, see runner-bean cultivation
No pruning required