A dangerous disease that attacks the capital’s most iconic tree was confirmed in London in 2011. S. platani has been rife in Germany and Holland for some years and has reached the UK. The disease affects the London plane (Platanus ‘x’ hispanica). These are some of the tallest of the capital’s trees and one of the most planted, lining thousands of urban streets and squares. The disease causes dangerous instability as the tree fights the infection by shedding branches. The cost potential for London’s councils and property owners is considerable as the health and safety implications cannot be ignored. There is no ‘disease-resistant’ option for the London plane. The existing trees will have to be treated or lost and treatment, by injection and bark applications, is possible.