The K6 has since become a British icon, but it was not universally loved at the start. The red colour caused particular local difficulties and there were many requests for less visible colours. The Post Office was forced into allowing a less strident grey with red glazing bars scheme for areas of natural and architectural beauty. Ironically, some of these areas that have preserved their telephone boxes have now painted them red. The paint colour used most widely today is known as "currant red" and is defined by a British Standard, BS381C-Red539. This slightly brighter red was introduced with the K8 model in 1968, but went on to be used across the estate on previous models too. Hence, for complete historical accuracy, any kiosks in pre-1968 settings should really be painted in the previous, and slightly darker, shade BS381C-Red538.