Letters between Mahatma Gandhi and the man some say was his gay lover are to go under the hammer at Sotherby’s auction house in London.

The correspondence, papers and photographs, which were owned by German Jewish bodybuilder Hermann Kallenbach, are expected to fetch between £500,000 to £700,000 ($777,000 to $1.1m).

Kallenbach became a close friend of Gandhi after meeting in Johannesburg in 1904 and their bond has been the subject of speculation after his biographer Joseph Lelyveld hinted at a more ‘intimate’ relationship in his book Great Soul: Mahatma Gandhi and His Struggle.

However, the Pulitzer Prize winning author denied there was any sexual element to the pair’s relationship.

Gabriel Heaton, a books and manuscripts specialist at Sotheby's, said while the letters were important in shedding light on the leader’s life and his friendship with Kallenbach, the content is not of a sexual nature, reported The Times of India.

However, Lelyveld claims that Gandhi destroyed the ‘charming love notes’ to him because he believed Kallenbach wanted them to be seen ‘by no other eyes’.

Gandhi is revered by Indians as the ‘father of the nation’ after spearheading the independence movement against British occupation.

Other letters in the collection include those written by Gandhi’s family and other friends.

The Indian government had previously tried to buy the letters from Kallenbach’s niece in Israel but the asking price was too high, reported The Times of India.