In 1940, 12-year-old Cuban boy Fidel Castro wrote to US President Franklin Roosevelt to request a $10 note.

The hand-written letter, embellished with an elaborate signature, has been unearthed by the US National Archives and Records Administration.

It was one of the thousands of letters sent to the White House by children taking their demands to the very top.

In an impeccable hand, young Fidel signs the letter to President Roosevelt : "Your friend".

Dear Mr President

He asks Roosevelt, President of the US between 1933 and 1945, to fulfil one desire - to send him a green $10 note.

"Never I have not seen a ten dollars bill green American and I would like to have one of them," the future Cuban leader wrote.

He included a return address at the Colegio de Dolores in Santiago, Cuba, where he was studying at the time.

The White House had an office to deal with all the president's correspondence and sure enough Fidel Castro received a reply, but disappointingly, no bill.

About 19 years later, his guerrilla campaign toppled the seven-year military rule of Cuban President Fulgeneio Batista and, at 32, Mr Castro became the country's new leader.