Mao's letter bearing his and Zhu De's signatures.[Photo/China Daily]

A letter from Mao Zedong appealing to the leader of the British Labour Party in 1937 for help against Japanese invaders has sold for 605,000 pounds ($908,000) at auction in London.

In the letter, typed in English and signed by Mao, a founder of New China, asks Clement Attlee, Labour leader and a future prime minister, to lend the support of his party to "any measures of practical assistance".

The buyer at Tuesday's auction was a Chinese private collector, auction house Sotheby's said in a statement.

The letter was one of the first communications between the Chinese leader and a Western politician, and only the second letter from Mao to be sold at auction in decades, Sotheby's said.

It is dated Nov 1, 1937, and was written in Yan'an in northwestern China, where the Red Army was based after the 1934-35 Long March.

In the letter, Mao expressed solidarity with the British people and hoped they would urge the government to help him resist the Japanese invaders, saying this was "a danger that ultimately threatens them no less than ourselves".

"Long live the Peace Front of the Democratic Nations against Fascism and Imperialist War!" concludes the letter, which was also signed by Zhu De, one of the founding generals of the People's Liberation Army.