Somen Debnath says he spent more than three weeks blindfolded strapped to a chair in a pitch-black 10ft by 10ft dungeon.

He said that he was travelling through Afghanistan as part of a five-year bicycle ride through 33 countries to promote Aids awareness.

Armed militants assumed he was a spy and kept him captive in Herat.

Unable to understand his captors'' commands, Debnath, 28, was regularly beaten for disobeying orders, starved and repeatedly told he was going to die.

But after realizing that one of his captors had a very basic grasp of English, he convinced him to allow him to cook them all a meal.

The Taliban kidnappers were so impressed with his banquet they decided he was ''safe'' and let him go.

Debnath said: ''I cooked hot, spicy Indian food for them the way we have it in the Sunderbans in India. They were very happy and told my interpreter that I seemed to be a safe guy. In the meantime, I had chatted up the interpreter and through our short exchanges, made it clear that I was just a man who was out on adventure and had no intentions of harming their cause.”

''The interpreter must have passed this on and I was set free after 24 days. The first sunlight which hit my eyes out in the open almost blinded me,' he recalls

Debnath, who has a degree from India in zoology and fine arts, set off on his bike from his village of Sunderbans in 2004.

His plan was to visit 191 countries by 2020 to highlight the plight of Aids across the globe and entered Afghanistan across the Pakistan border earlier this year.