REVELLERS relieving themselves on Pamplona’s medieval walls during this week’s famous San Fermin festival are in for a shock.
Scientists have created an invisible water-resistant paint which repels urine back onto the offender’s trousers and shoes.
Street urination among festival goers has been a recurring problem causing damage to the walls and costing an estimated €10,000 to clean up.
Last year 76 people were fined by police for urinating in public.