Seven hot-air balloons are soaring above London to signal the one-year countdown to the 2012 Olympics

Londoners are being serenaded from the sky to herald the one-year countdown to the London 2012 Olympics.

The serenade of Londoners from the air is the work of Luke Jerram's Sky Orchestra

Ahead of Wednesday’s ceremony in Trafalgar Square, seven hot-air balloons are being launched in the mornings and evenings this week playing sweet melodies from high above the capital.

The musical reminder of the milestone date in the run-up to the Games is the work of artist Luke Jerram’s Sky Orchestra. It has come about through a tie-up between the London International Festival of Theatre (LIFT) and London Mayor Boris Johnson.

Each of the balloons is broadcasting a different element of a musical score composed by award-winning British musician Dan Jones, amplified to be heard by people at ground level.

It has been designed as a preview of the cultural events and celebrations being organised to coincide with London 2012.

Mark Ball, artistic director and chief executive of LIFT, described it as a “blue skies project” but said it is “no casual thing” to fly hot-air balloons across a major city, with input needed from many organisations including flight controllers at Heathrow and City airports.

Mr Jerram described it as “A form of acoustic urban art”, and added: “The aim is to lift the sleeping public into a space on the edge of sleep, and to inspire their imaginations through sound.”

Mr Johnson said: ‘With a year to go to the 2012 Games, London is waking to one of the most exciting periods in its illustrious history. As the Sky Orchestra floats gracefully across the capital’s skyline, it provides a stunning preview of the astonishing variety of cultural events and activities that people will be able to experience.”

Munira Mirza, mayoral advisor on culture and youth, said: “Sky Orchestra is one of those ingenious, breathtaking ideas that epitomises London. This is the city that serenades you whilst you eat your cornflakes.”

The musical balloons follow Open Weekend 2011, which featured more than 1,200 projects, sporting and cultural activities in London and across the UK.

The London 2012 Festival will be a 12-week cultural celebration next June to September as the climax to the Cultural Olympiad.

Throughout the year there will also be many other events taking place in all 33 London boroughs, including outdoor arts activities in town centres, installations in unusual places around the city and live performances at public spaces.

If you’ve seen the musical balloons floating overhead send pictures or video to simon.bull@archant.co.uk