The 26-year-old from Majorca, an 11-time Grand Slam winner, was set to be one of the biggest stars at London 2012 and was also to be Spain's flag bearer at the Opening Ceremony on July 27.

But Nadal has dealt his country and the Olympic Games a major blow by announcing he will not be travelling with the Spanish squad to the Athletes' Village London

"It is one of the saddest moments of my career," Nadal said in a statement.

As well as the London 2012 men's singles competition, Nadal was also scheduled to compete in the men's doubles at the Olympics alongside Marcel Granollers, but will now play no part in either competition.

The world number three has long struggled with tendinitis in his knee and fears over his participation at the Olympics increased after a recent exhibition match against Novak Djokovic in Madrid was cancelled due to the problem.

Nadal's last match took place during the second round of Wimbledon last month where he was eliminated shockingly by Lukas Rosol, then ranked world number 100, of the Czech Republic.

The London 2012 Olympic competition is set to take place at Wimbledon, where Nadal – as two time Wimbledon champion in 2008 and 2010 – would have been one of the favourites for gold.

Nadal holds up the Spanish flag after receiving his gold medal at Beijing 2008

Shortly after defeat to Rosol, Nadal admitted he was not 100 per cent and faced a race against time to make it to London 2012.

"I am doing everything possible to recover," he said.

"I am working as hard as I can and hopefully I will be at 100 per cent.

"I am the one who is most worried.

"I hope that things improve and my intention is to arrive in London well prepared and recuperated.

"It is for this that I work every day.

"Carrying the flag will the something unforgettable and I hope that Spain continue on the path of success it has been on for the past few years."

But despite the heartbreak for Nadal, his exit is likely to be good for Britain's Andy Murray as the Spaniard was set to be one of his biggest rivals for gold.

Murray lost out to Swiss star Rodger Federer in the Wimbledon final this year in four sets following a brave performance.

The pair will be two of the biggest contenders for Olympic gold, along with Serbia's Djokovic.

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