Ali Mansur was the manager of the canteen at the R.A.F. station at Dum Dum Airport, Calcutta, during the events narrated in Biggles in the Orient. Mansur was a retired sergeant of the King's African Rifles, with twenty four years of service, a Distinguished Conduct Medal and a Long Service Medal. Described as an elderly, dark-skinned heavily moustached man, Mansur had a soldierly bearing and wore medal ribbons on the lapel of a spotless white jacket.
Called to investigate a string of mysterious aircraft disappearances in India, Biggles had concluded that one of the prime suspects was the mess steward Lal Din. Air Commodore Raymond was insistent on settling the issue swiftly so Biggles confronted Lal Din but this only led to the servant committing suicide before he could be forced to say anything. Apparently at a dead end, Biggles decided that one remaining avenue was to check if anybody had been making enquiries about Lal Din.
There was a need to move fast before the leaders of the spy ring suspected they had been compromised. Biggles decided to approach Mansur who, as canteen manager, must know something of Lal Din's background and movements. Biggles decided to take Mansur, who he regarded as above reproach because of his service record, into his confidence.
In the event, Mansur proved extremely helpful. He told Biggles that someone who called himself Lal Din's brother had occasionally called for Lal Din. Mansur had himself employed Lal Din on the recommendation of Mr Larapindi, a wealthy merchant. Mansur described him in some detail for Biggles and told him that Larapindi's firm, Tahil and Larapindi supplied the canteen with, among other things, confectionery like chocolate and chewing gum. He also told Biggles that there had been a recent free issue of chocolates and chewing gum and Lal Din had offered to distribute it. Thus supplied with fresh leads and new suspects, Biggles was able to push on with the investigations, set a trap for Larapindi and bring down the spy ring.