THERE is a scene in On Dangerous Ground in which protagonist Sean Dillon finds himself in a sticky situation on the Thames Embankment, confronted by an albino with a large gun. His bacon is saved by the owner of a nearby Chinese restaurant, Yuan Tao, who sees off the albino and some of his thuggish friends, then turns to Dillon and says: ''I should explain, Mr Dillon; I am a Shaolin monk, if you know what that is.'' Dillon, a British Intelligence know-it-all, does know what it means. ''It means, I suspect, that you're an expert in kung fu ?'' The exchange does not take place in English because Dillon also speaks Cantonese. It is a significant scene in two respects. Firstly, it is a microcosm of much of the plot; secondly, the characters in it are a perfect illustration of how Higgins has failed to invent anyone new. In medieval England, writers who took other people's ideas and turned them into popular works were known as the kings of shreds and patches. It is a mantel that these days might be applied to Higgins, except he's doing it to himself. The millionaire author of The Eagle Has Landed and 51 other books has grown lazy. Certain elements in On Dangerous Ground were inspired by one of his earlier works, Midnight Never Comes, published in 1966. Much worse are those characters. Yuan Tao is a Shaolin monk and restaurant owner, a typical Hong Konger, visiting England to check his business interests. His niece, Su Yin, is inscrutable, beautiful and obedient. Dillon sleeps with her, but in between, her dialogue is limited to pleasantries such as: ''Yes, Uncle, I will get the supper now.'' Dillon has been shot saving the life of the British prime minister and the American president. Yuan Tao, after helping him out with a spot of kung fu on the embankment, befriends him and nurses him back to spiritual health. His role, and that of his niece, is a brief one, allowing Higgins to trawl through the dregs of Eastern mysticism: Man's intrinsic energy (the ch'i), Taoist verse and secret societies. The real plot centres on a document known as the Chungking Covenant, which could extend the British lease on Hong Kong. It was signed by a Cantonese-speaking Mao Zedong and Lord Louis Mountbatten and then lost in a plane crash at a remote Scottish loch. British Intelligence wants the covenant and so does the Mafia, which is keen to extend its dubious interests in the colony for a further 100 years or so. What follows is predictable and uninspiring.