China’s failure to crack down on the production of copycat versions of the Dyson Air Multiplier, the bladeless fan launched two years ago, has trimmed profits growth at one of Britain’s best-known companies.

The Wiltshire-based manufacturer, founded by Sir James Dyson and best known for its bagless vacuum cleaners, saw turnover rise from ￡770m ($1.3bn) to ￡887m while operating profits jumped from ￡190m to a record ￡206m in the year to December. Pre-tax profits including exceptionals rose from ￡164m to ￡198m.

The trading improvement was achieved in spite of tough high street conditions in many key markets for the first full year of sales of its bladeless fan range, which is proving particularly popular in Japan. Further extensions to its range of vacuum cleaners and progress in marketing its Airblade hand dryer across Europe also boosted turnover.