Nowadays people listen to music when they are out on a smartphone or if you're feeling retro, an MP3 player, but on this day 40 years ago the Sony Walkman was launched, paving the way for the personal music player.

The Sony Walkman was the very first portable cassette player when it launched on July 1, 1979 and went on sale for around £120.

It changed the way people listened to music when it was initially launched in Japan.

The blue and silver TPS-L2 came to the USA a year later and become a sell-out success.

In its 30 year production span, more than 220 million cassette players were sold around the world.

A double audio-jack was a feature on some of the models, so you and a friend could listen together.

Walkman paved the way for portable music players in the years following its launch. Credit: AP

In 2010, Sony stopped production of the cassette Walkman, but in 1984, it launched the Discman, the first portable CD player.

Since then, the Walkman has been overtaken by many other portable players, notably the Apple iPod, and now, most people's mobile phones, but it's safe to say the Walkman was the pioneer in the field of playing music on the go.