It is a big enough market even if it declines at a few percent a year. The scale is so great that the decline would be incredibly slow." Coronavirus could generate other new business for De La Rue. The company's technology is being used to develop authentication stamps for tests for the disease, along with "immunity passports", but these are at an early stage – although discussions are being held with several governments. The chief executive was speaking as De La Rue posted annual results for the year to the end of March.