Mr Blue Sky is the Electric Light Orchestra's brilliantly off-beam classic song.

It was released as a single in 1978, having first appeared on the ELO album 'Out of the Blue' in 1977. Written by Jeff Lynne, it was a no.6 hit in the UK, and has endured on the radio airwaves ever since.

Tracey Collinson whose husband, Nigel, loved the track tells of the meaning it has for her.

Musicologist, Allan Moore, discusses the anomolous use of the word 'blue': usually associated with downbeat emotions, this is a peculiar subversion of that cultural norm with the word 'blue' conjuring happiness and good weather.

Tremayne Crossley and his friend, Jo Milne, tell the extraordinary story of how Jo heard music for the first time. This track played an important role in that event.

For Dr. Sam Illingworth, Mr Blue Sky will always take him back to the low-flying research-flights he made over the wetlands, greenlands and seas of the Arctic Circle with the shadow of the BAE146 plane beneath him and clear blue skies above.

The children of King's St. Albans in Worcester sing the track featuring at the end of the programme.

Series about pieces of music with a powerful emotional impact

Producer: Karen Gregor

First broadcast on BBC Radio 4 in November 2015.