The 68-year-old star became the first British act to win the singing competition in 1967 with her hit Puppet on a String, but she has been left out of the upcoming Eurovision Greatest Hits concert taking place in London on March (15). The show will feature highlights from the past 60 years from the competition, including a performance 2014 winner Conchita Wurst.

Shaw, who retired from singing in 2013, was not approached to perform and her offer to host a section of the concert was not taken up by producers.

In a post on Facebook.com, the singer writes, "I did not know about the 60th live show until this weekend. I have not offered to sing on it. I have not been asked to sing on it... I did offer last month as a gesture of support of the 60th celebration to do some hosting which I believe is more appropriate but did not receive a positive response.

"I do not know why I have not been asked to be involved... I just got fed up with being asked by all and sundry and not being in a position to respond... It is probably based on complete misunderstandings. These things always are."

A BBC spokesman tells Britain's Daily Mail newspaper, "(It is) a 90-minute show... it would be impossible to include all 1,400 acts that have entered the contest over the years... This means that difficult decisions have to be made regarding the line-up on the night..."

The concert will be hosted by British TV star Graham Norton and former Swedish contestant Petra Mede at London's Hammersmith Apollo on 31 March (15). It will be broadcast on TV across Europe at a later date.