Sir Cliff Richard was cheated of victory in the Eurovision Song Contest of 1968 by General Franco�s fascist regime which rigged the contest to boost Spain�s image, a documentary has claimed.

The Spanish entrant Massiel won the competition forty years ago with the ditty 'La, la, la' robbing the British crooner of the title by only one point in a nail-biting finish.

Sir Cliff, who was knighted in 1995, represented the United Kingdom with the hit song 'Congratulations' in the contest in April 1968 held at London's Royal Albert Hall and strongly led the competition until the last moment when Spain's entry surged ahead.

A documentary filmmaker has now revealed that Spain's only ever Eurovision win was down to behind the scenes negotiations by television executives from Spain's state run channel.

Director Montse Fernandez Vila claims that RTVE (Spanish broadcaster) executives toured Europe offering cash and promising to buy television series and contract unknown artists from other Eurovision member states to influence the vote in the prestigious singing competition.

”There is evidence that votes were bought to secure a win for Massiel,” said the director discussing the documentary “1968. I lived through the Spanish May”, broadcast on Spain's Sexta channel.

At the time the winner of the competition was decided by a jury comprised of 10 members from each of the 17 countries participating. Each member awarded one point to their favourite song.

With the emerging tourist industry on the Spanish Costas the regime of fascist dictator General Francisco Franco hoped that a Eurovision win would boost its popularity both at home and abroad.

”The regime was acutely aware of the need to improve their image,” Ms Fernandez Vila told Spanish daily newspaper 20 Minutos.

"Looking back at the parties that were organised and the way Massiel was turned into a national hero – it seems a bit excessive for a song festival but it all served to glorify the regime,” she said.

Massiel, now 60, whose real name is Maria Felix de los Angeles Santamaria Espinosa, went on to become one of Spain's best loved singers and re-released her Eurovision entry in 1997 with a hip hop beat.

The song 'La la la' sparked controversy from the start. The original version penned by Duo Dinamico was in the Catalan language but the Franco regime insisted the words be sung in Spanish.

Sir Cliff, now 67, made a second attempt to win the Eurovision Song contest when in 1973 he represented the UK with “Power To All Our Friends”. But he only reached 3rd place behind artists from Luxembourg and Spain.

In Britain he has sold more records than either Elvis or the Beatles – his worldwide sales total 250 million – and he was the first rock star to be honoured with a knighthood.