The prince of thieves, may also have been the forest queen.

New studies of the medieval texts that first recorded his deeds suggest that the robber with a heart of gold was actually a gay outlaw who had been exiled from "straight" society. Little John, not Maid Marian, was his true love.

The revelation flies in the face of Kevin Costner's portrayal of the outlaw in "Robin Hood: Prince of Thieves", and suggests that the title of Mel Brooks's film "Robin Hood: Men in Tights" may have been closer to the mark.

The reassessment is based on studies of the 14th-century ballads of Robin Hood, the earliest known accounts of his deeds, which detail his relationships with his "merrie men", especially Little John and Will Scarlet.

Stephen Knight, professor of English literature at Cardiff University, said the ballads, the first and most authoritative accounts of Hood's deeds, had clear homoerotic overtones.

He said: "Robin Hood and his men are all very male and live exclusively without women. The ballads could not say outright that he was gay because of the prevailing moral climate, but they do contain a great deal of erotic imagery. The green wood itself is a symbol of virility and the references to arrows, quivers and swords make it clear, too."

The ballads were written in Chaucerian English, made more complex by a strong dialect. One translation includes the verse: "When Robin Hood was about 20 years old; he happen'd to meet Little John; A jolly brisk blade right fit for the trade, for he was a lusty young man."

The ballads also show that Maid Marian - usually depicted as Hood's true love - never existed.

Knight believes she was added by 16th-century authors who wanted to make their works more respectable to heterosexual readers. He will present his research to fellow academics in a paper called "The Forest Queen" at a three-day conference in Nottingham organised by the University of Glamorgan this week.

The conference will include trips to places where Robin Hood and Little John are said to have lived together.

In modern times Hood has been depicted as a minor aristocrat who becomes an outlaw after his lands were confiscated in the 1190s by King John. He fights against the unjust king and his lackeys, famously stealing from the rich to give to the poor.

He is finally rehabilitated when Richard Lionheart, the rightful king, returns from the Crusades and makes Hood the first Earl of Huntingdon, a title that still exists.

The ballads, however, suggest a different story. They indicate that the real Hood almost certainly came from yeoman or peasant stock, that he roamed Nottinghamshire and Yorkshire in the late 13th or 14th century and that his popularity came not from giving away money but from his ability to flout authority.

One of the earliest works, "Robin Hood and the Monk", written anonymously in about 1450, describes the intimate friendship between the outlaw and Little John. It depicts them having a row over money that Knight describes as "almost domestic".

It is resolved only when Little John rescues his leader from their enemies. Similar themes are explored in "Robin Hood and Guy of Gisbourne" - again Hood and Little John fall out but are reunited.

Some historians believe that Hood was a genuine character,but that ballads have been embellished with the exploits of other outlaw gangs, among many of which homosexuality would also have been common.

Barry Dobson, professor of medieval history at the University of Cambridge, agrees with Knight that the relationship between Hood and John in the ballads is "ambiguous".

He said the 13th century had seen increasing oppression of gays: "In the 12th century homosexuality was accepted, but in the 13th the church became much less tolerant and such people were driven underground."

Peter Tatchell, spokesman for the gay rights group Outrage!, which became notorious for exposing prominent people who had not declared their homosexuality, said the outing of Hood was long overdue.

"His lifestyle alone was enough to provoke speculation," he said. "It's about time school history lessons acknowledged the contribution of famous homosexuals."

But the idea that the tales of Robin Hood should be given a gay twist horrifies those used to seeing him as being "straight as an arrow".

Mary Chamberlain, secretary of the Robin Hood Society, accused the academics of trying to make their name at the expense of England's best-loved folk hero. She said: "Robin remains a highly regarded figure the world over and children like to play at being Robin Hood. These claims could do a lot of damage."

Hood's alleged descendants may also be dismayed. The Huntingdons' pride in their ancestry led to the current earl and his father both being given "Robin Hood" as their middle names.

This weekend, however, the current earl, William Edward Robin Hood Hastings Bass, swiftly distanced himself from the "gay" outlaw, claiming that they were not related after all.

He said: "It's a nice myth that Robin Hood was the first Earl of Huntingdon, but there is no historical evidence that he really was linked to my family."