The test was carried out by the Swedish Trade Federation, which represents Swedish businesses, also found that playing no music at all was better than playing random popular music, with random music cutting sales by more than 4pc compared with silence.
Last year Marks and Spencer decided to switch off background music in stores for the first time in a decade after customers complained about the noise.
The new music-free policy was thought to be designed to please Marks and Spencer’s aging customer base, as experts said elderly people with hearing problems and dementia can find background music disorientating and make shopping less enjoyable.