Hill tribes take part in a vibrant procession to begin the annual Akha Swing Festival in northern Thailand.

Indigenous people from six groups converge on the village in the mountainous Chiang Rai province each year for the colourful festival.

The Akha people, who have been settled for several decades in the region, celebrate their freedom with a colourful swing festival.

The symbolic act celebrates throwing off the bonds of constraint and is also the tribe's new year celebrations, in line with the peak of the rainy season.

''When you don’t have your country any more, you still can feel free while swinging in the air,'' plays their Akha New Year song.

Hundreds of tourists now visit the remote region, sometimes only accessible by motorcycle to watch the spectacle.

It begins with a raucous procession along the mountain road before the Akha tribe swings on a bamboo pole and the people perform traditional dances.

The unique festival is one of the most recognizable in Thailand, with five other tribes which wear different costumes joining in with the event.

Historians once described how the Akha villages would ''reek of opium'' and that they were the ''most unhealthy and miserable of all mountain tribes''.

However, government and charity schemes to replace opium poppy cultivation with other income has transformed their lives.

The late Dr. Leo Alting von Geusau, an expert on the tribe, wrote: ''For centuries they have fled suppression. So, when missionaries and anthropologists described them as semi-nomadic, this was a rather slanted interpretation of the real situation.

''They are born losers who have internalized their fate. Mere survival has become the core of their culture. They regard the outside world with great suspicion, as being full of potential evil forces. Even now, visiting officials are regarded with distrust and spoken to with sweet words and offered glasses of rice liquor to appease them.''