Sir James Dyson has won a victory in the European courts over EU tests that — his company says — unfairly penalised its vacuum cleaners.

An appeal in the European Court of Justice said that a previous ruling against the business had “distorted the facts” and “erred in law”.

Sir James has been contesting an EU ruling that requires vacuum cleaners to carry labels showing their energy efficiency and cleaning performance as part of a ‘green’ drive by Brussels.

He has argued that “the tests are only relevant to vacuums when their dust bags are empty, not when they are full, as they would typically be in normal use; a full vacuum would typically use more energy.”

Dyson’s machines use a design without a bag to collect dust, and the company argued that the tests “unfairly disadvantaged” its products.

“The European Court of Justice agrees, saying that the tests should “measure the performance of vacuum cleaners in conditions as close as possible to actual conditions of use”.

Meanwhile, Sir James said in an interview with The Times that he only receives six e-mails a day. When he founded the company 30 years ago, he banned staff from writing memos and encouraged them to talk to each other instead.

He gave new recruits exercise books (he still does) and tells staff to use them in meetings instead of laptops.

In contrast, Apple CEO Tim Cook says that he receives 700-800 messages per day and wakes up at 3.45am to read them all.